I started another thread about the Extra Attack feature stacking for Two-Weapon Fighting to give the mechanic a boost as the mechanic is generally considered weak in 5e. However I have since come to the conclusion that that was not the best way to go about improving Two-Weapon Fighting. Instead of continuing a discussion on Two-Weapon Fighting in a thread unrelated by name, I decided to start this thread up.
To start up the discussion I think we need to understand why the mechanic is considered poor by many - even a majority I believe.
Pros:
You can use your bonus action to get damage (with investment in the Two-Weapon Fighting Style, you treat it basically like +1 weapon attack, with some restrictions).
More attacks means more consistent damage output although not necessarily the highest - basically you have more chances to make a hit the more attacks you make in a turn. This is especially useful for characters that have an on-hit damage proc, like Sneak Attack, Barbarian Rage or the bonus damage from say Spirit Shroud.
More attacks means more opportunities to break enemy spell concentration (although TBF that is generally not a major player before you hit level 8+).
Cons:
It hogs your bonus action, and many class features utilize their bonus action to gain significant benefits like damage or utility.
You are limited to light weapons for both your main and off-hand weapons, unless you invest into Dual Wielder to get +1 AC, +2 to your damage dice on both weapons and a technical benefit for double drawing/stowing that really shouldn't exist (and many DMs don't enforce it), but if we count it, it counts as another negative point against Two-Weapon Fighting.
You don't get your ability modifier applied to the damage rolls for your off-hand unless you pick up the Fighting Style, limited to Fighter and Ranger or the Fighting Initiate feat. With the Fighting Style you generally see a damage advantage over a standard two-hander like the Greatsword's 2d6. As soon as you hit level 5 and get the Extra Attack feature, the advantage is gone. And from thereon it only gets worse for the TWF.
You forego picking up Great Weapon Master and it's worth mentioning Polearm Master too for the bonus attacks on enemy entering threat-range and its interaction with a feat like Sentinel. Polearm Master even includes a bonus action off-hand attack (that do count your ability modifier), if you got nothing to use your bonus action on.
You have weapons in both hands, meaning spell casting with somatic components is a no-go unless you grab the War Caster feat or utilize shenanigans with Hexblade's Improved Pact Weapon as a Spell Casting Focus, casting Warlock spells with a material component. (Or do some stow/draw action that is generally frowned upon).
Lesser Opportunity Attacks (comparing damage between a Shortsword and a Greatsword/Polearm for an OA is not a good feeling)
Lessened benefit from extra actions like those from Haste or Action Surge, especially hurting with the loss of access to Great Weapon Master.
Finding two magic weapons is more problematic than finding/acquiring one.
With a plethora of drawbacks, mainly stemmed in action economy and damage scaling, it would seem that Two-Weapon Fighting is not a great combat style for the general adventurer. So this thread is to explore some changes to existing rules, or additional rules, or new feats (investment options). Technically it could also be something like minor or moderate properties for magic items.
Do you have any ideas on how to improve Two-Weapon Fighting?
We already had some ideas from the previous thread that I will post here:
The original idea of the previous thread I posted was to allow the Extra Attack feature to stack when used with Two-Weapon Fighting. Thus if you acquire the Extra Attack feature from say a level 5 Fighter and a level 5 Paladin, you could stack them. It would only work when you were using your Bonus Action to make an attack through the Two-Weapon Fighting rules and you would have to attack twice with each weapon. I came to a rough ruleset that would be put into the PHB under chapter 9 about Two-Weapon Fighting with the following text:
"If you have two instances of features or abilities that grant extra attacks when taking the Attack action, like the Extra Attack feature, Warlock's eldritch invocation Thirsting Blade, Tenser's Transformation, etc. you can instead use your bonus action to attack twice with the weapon in your other hand when using Two-Weapon Fighting unless you have already attacked with that weapon during this Attack action. You cannot attack with that weapon further during this Attack action. You ignore these limitations if you make or made attacks with that weapon during a separate action - like the additional action gained from the Haste spell."
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Another idea posted in the thread was a Great Weapon Master equivalent feat:
I would generate another feat and allow that stack with existing feats and (sub)class features. I have in my mind this image of a martial combatant who attacks with both weapons in coordinate combination of strikes. Similar to a boxer or an MMA fighter; using attacks to setup big more power blows or quickly striking so to hit their opponent two, three, or even for times with their attacks. The draft for the feat would look something like this:
Combination Attacker
You are a master of welding a weapon in each hand and have perfected techniques that allow you to attack by using a combination of strikes.You gain the following benefits:
When you take the ATTACK action and hit a creature, you may immediately use your Bonus Action (if available) to attack the same creature with advantage using the weapon in your other hand.
When you score a critical hit with a melee weapon, you may make a regular damage roll for the weapon in your other hand and add the rolled value to your critical hit damage.
When you take the ATTACK action, before you make a melee attack with a weapon that you are proficient with, you can choose to take a -5 penalty to the attack roll. If the attack hits, you add +10 to the attack's damage.
This would stand alone as a feat and does not require, but would benefit from, taking Dual Wielder or the two weapon fighting style. I think is adds in some power to the damage capability for a character that opts to fight with weapons in both hands; making the two weapon combatant have more impact in the game.
Both are basically variants of the Great Weapon Master feat. Personally I found that making a GWM variant would be uninteresting and wouldn't set two-hander combat styles apart from two-weapon fighters. And you run the risk of the TWF variant being the better damage option that overshadows GWM.
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Another idea was to remove the Bonus Action cost to Two-Weapon Fighting if you have the Extra Attack feature (or equivalent). Evening out the playing field against a two-hander like a Greatsword, dealing roughly the same damage and without costing the TWF their Bonus Action for no apparent gain. Greatsword with their 4d6 + 2xASM (ability score modifier) and the TWF with 3d6 + 3xASM - at level 5 ASM is assumed to be a +3.
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I brainstormed a handful of bulletins that could be used for making new feats:
Whenever you attack with a melee weapon that you wield in one hand and you are proficient with, you may take a penalty to your attack roll up to your proficiency bonus (any number between 0 and your proficiency bonus). If the attack hits, you add that amount to the damage roll.
Whenever you attack with a melee weapon that you wield in one hand that you are proficient with, you may add half (rounded down) of your ability score modifier for Strength or Dexterity (your choice) to the damage rolls of that attack. If that ability score is 20 or higher you round up instead. You cannot use the same ability score modifier through this feat that you are already using for your attack.
While you are wielding a non-heavy melee weapon in each of your hands and an enemy within 5 ft. of you attacks you but doesn't hit, you may use your bonus action or reaction to make one weapon attack against that enemy.
While you are wielding a non-heavy melee weapon in each of your hands and an enemy within 5 ft. of you attacks you, you may use your bonus action or reaction to have that enemy attack at disadvantage with that attack. You may use this ability after the enemy has rolled for attack but before the outcome is determined.
While you are wielding a non-heavy melee weapon in each of your hands and with which you are proficient, you may use your bonus action to not provoke opportunity attacks this turn.
Whenever you take the disengage action while wielding a non-heavy melee weapon in each of your hands and with which you are proficient, you may make one weapon attack against an enemy within reach.
First, in my opinion if we are trying to improve the general concept of Two-Weapon Fighting which is a core rule / mechanic for combat from the PHB Chapter 9, then the solution should not be to add a feat that creates better balance. Remember, Feats are technically optional rules according to the books. Core mechanics should be balanced assuming a game where the DM does not allow feats. If some feats currently exist which makes one type of build more powerful than another then that is a separate issue of the balance and quality of the Feats which have been officially published so far -- for our purposes here I believe that the existing feats should generally be ignored.
Here is my current solution which is somewhat simplistic (in keeping with the general 5e design choice of higher simplicity and less granularity) and is probably overpowered:
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Two-Weapon Fighting
When you take the Attack action and attack with a light melee weapon that you're holding in one hand, you can use a bonus action to attack with a different light melee weapon that you're holding in the other hand. You don't add your ability modifier to the damage of the bonus attack, unless that modifier is negative.
If either weapon has the thrown property, you can throw the weapon, instead of making a melee attack with it.
If your Attack action allows for more than one attack and you make all of those attacks with a light melee weapon that you're holding in one hand, then in-between each of those attacks you can make one additional attack with a different light melee weapon that you're holding in the other hand. You don't add your ability modifier to the damage of the additional attacks, unless that modifier is negative.
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As a Fighter makes progress, this would allow for the option to make the following attacks:
Like I said, this is probably too much. I considered tacking on a statement to the end such as the following: "For every additional attack taken your AC is reduced by 1 until the start of your next turn." But I'm not convinced that such a tradeoff makes sense thematically.
It is mostly considered "weak" in the context of feats like great weapon master, polearm master, cross bow expert and sharpshooter. Two weapon fighting doesn't have a feat that gives a comparable boost to damage as great weapon master or sharpshooter. If you compare two weapon fighting with two short swords and the fighting style vs a long sword and shield with the fighting style then the damage comparison is more reasonable.
longsword = 4.5+2 = 6.5 +stat
Short sword = 3.5 +stat
Short Sword off hand = 3.5 + stat
Two weapon fighting is 7 + 2 x stat vs 6.5 + stat in tier 1 for a fighter. Tier 2 this becomes 13 + 2 * stat vs 10.5 + 3 x stat .. for a 16 stat this is 19 vs 19.5 for 18 stat it is 21 vs 22.5 at the expense of 2 AC due to the lack of a shield.
Comparing to a greatsword ... the numbers are 8.5 + stat (GWF adds about 1.5) vs 7 + 2 x stat in tier 1 and 17 + 2 x stat vs 10.5 + 3 x stat. However, the TWF gives two chances to hit, meaning more opportunities to smite or sneak attack.
Basically, TWF isn't that far off the baseline of other attack options for martial classes. The real difference shows up when you start comparing feats that increase damage or provide additional attacks ... while TWF has the lackluster dual wielder feat increasing AC by 1 and allowing the character to use weapons that aren't light ... which amounts to a +2 increase in damage in tier 1 and +3 in tier 2 (1 point/attack due to using a d8 weapon instead of a d6 and a slightly better AC).
If you want to improve TWF, then I'd suggest looking at adding a feat that boosts damage and reduces to hit comparably to GWM/SS. Maybe something like Decisive Flurry -3 to hit and +5 to damage for each weapon attack while dual wielding. (Need to do the math to get the appropriate modifiers).
It is mostly considered "weak" in the context of feats like great weapon master, polearm master, cross bow expert and sharpshooter. Two weapon fighting doesn't have a feat that gives a comparable boost to damage as great weapon master or sharpshooter. If you compare two weapon fighting with two short swords and the fighting style vs a long sword and shield with the fighting style then the damage comparison is more reasonable.
<snip>
If you want to improve TWF, then I'd suggest looking at adding a feat that boosts damage and reduces to hit comparably to GWM/SS. Maybe something like Decisive Flurry -3 to hit and +5 to damage for each weapon attack while dual wielding. (Need to do the math to get the appropriate modifiers).
The lackluster feats that can be used by TWF is definitely a source of weakness for the combat style. However I would go more basic and say that using the combat style costs you your bonus action. In the early stages, that translates to a slight damage advantage, so it has a trade-off (you pay the cost and reap the benefit). At level 5 with the Extra Attack feature, that advantage is nullified against a two-hander (the most comparable combat style because it also focuses primarily on damage) and also against a single one-handed weapon with the Duelist fighting style - just like you described. However the two latter do not have the cost of a bonus action and neither do they carry the baggage of opportunity costs that TWF does (see the OP's con list).
So TWF is somewhat comparable in damage to other combat style when taking your first attack action on each of your turns. However as soon as we start counting Opportunity Attacks, class feature bonus attacks, additional actions (like from Haste) the cracks starts becoming very visible. This is the disparity about weapon attack value. That is much lower for TWF than they are for basically any other combat style. And TWF has basically nothing to show for it.
A GWM variant is likely the easiest solution to make it more comparable (in terms of investment output). However that is also the least interesting solution and doesn't do much to separate TWF from a two-hander combat style. That's why one of the bulletins I brainstormed for a new feat was to utilize the same idea as GWM/SS - sacrifice accuracy for more damage, but then link it to your proficiency bonus and instead of -1 accuracy for +2 damage, it is 1-to-1. However to not just have a much worse GWM you could select how much you sacrifice, instead of being an on/off switch like GWM/SS. This means you wont get as much damage out of it, but you're more likely to actually apply the damage because you can more easily find a sweetspot where you can hit the enemy. This also means you can effectively pick it up earlier because the entrance penalty is not as steep as GWM. The feat would then also scale with your character level and proficiency is capped at +6 so it will never be a stronger damage option than GWM. The neat part is that it could easily be used for one-handers (sword-and-board or duelist builds) too, but it still provides more benefit/opportunity for a TWF build. The broader you can make these feats without sacrificing reason or the intended use the better. I would then suggest for this particular feat to also have some additional utility. One of which could be some additional benefit to Opportunity Attacks, Disengage actions or whatever.
I think something that would logically make sense would be to add a +2 to your attack rolls (to-hit) when fighting with 2 weapons. Your target now has two weapons they need to focus on dodging instead of one, and they don't know which you are going to swing with.
When you think about the benefit to all the fictional dual wielder fighters, it is typically being able to feint with one sword and swing with the other, or make a stab with one sword when the first sword is parried/guarded. So I think that an extra ability to hit and keeping the modifier would be a good place to start. This could even go into the feat, or that could just be kept for two non-light weapons + some AC. Then the Fighting Style might get you an additional bonus to AC (maybe a +1 to AC and a +1 to damage rolls, splitting the difference between Defense and Dueling).
Thing is that attack modifiers are seldom the issue when considering the Two-Weapon combat style (you generally get this through the proficiency bonus, ability modifier, magical bonuses and to a degree assisted by advantage on attack - such as through flanking). The problem for TWF is mostly damage/utility and particularly in the later stages of the game basically level 5+. While I agree that feinting and basically better ability to manipulate your opponent and their weapon is thematically a part of fighting with two weapons, however this design space is already being used by the Fighter's subclass Battle Master and its Maneuver class feature. So utilizing it for TWF should be handled delicately if at all.
<paraphrasing> Two-Weapon Fighting now grants a bonus attack with an alternate weapon whenever you make a weapon attack during your attack action, except the first weapon attack.</paraphrasing>
I kinda like this version. I'm not sold that this should be usable alongside the bonus action attack from standard TWF. 4 attacks at level 5 seems a bit... much. I would rather that it is an alternate use of TWF - basically granting each Extra Attack bonus an additional off-hand weapon attack for free (non-stacking - the Fighter's version don't stack but upgrade).
At Fighter level 11 this would result in a TWF having 3 main-hand weapon attacks and 2 off-hand weapon attacks for 5d6 + 5xASM, whereas a two-hander would have 3 weapon attacks for 6d6 + 3xASM.
This would have TWF have a slight damage advantage over a two-hander naturally for the attack action. However the two-hander has an advantage for Opportunity Attacks, extra actions/attacks and obviously still has GWM to bolster their damage output.
Two weapon fighting has problematic level scaling. Absent feats which are, frankly, balance problems in their own right, basic 2WF is overpowered in tier 1, fairly neutral in tier 2, and underpowered in tier 3-4.
Are we talking in terms of damage die for underpowered? Because imo the difference there is marginal. By the time you’re into tier 3, the average of up to 3 extra comparing a d6 to d12 is marginal, as almost no class or subclass is relying on straight weapon rolls at that point. The action economy issue assumes the class in question has a better use for the BA. Fighters rarely have a dedicated bonus action, and with Rangers it more comes down to tactics; if you’re expecting to bounce between targets, it’s arguably better to save the spell slot; a potential extra 2d6 is about the same value as 1d6+mod. Rogues have a larger suite of potential options, but having to decide between doubling down to attack or retreat is just a reasonable tactical balance, imo. Plus TWF on a Rogue is mostly just fishing for a second chance to proc Sneak Attack if your first attack misses. In all, no one seems particularly crippled by spending a Bonus Action on TWF.
Here are the three core problems I see with Two-Weapon Fighting in 5e:
The core benefit of being able to attack with your Bonus Action is duplicated by many features and always in a better form. Two-Weapon Fighting requires no investment beyond having two appropriate weapons and so is initially the optimal approach in most situations. Once a character starts to level and gains access to features and feats like Martial Arts or Polearm Master, Two-Weapon Fighting becomes strictly the inferior option. Two-Weapon Fighting requires no investment but mechanically is just the worst way to weaponize your bonus action.
The feature that gives the biggest increase in effectiveness to Two-Weapon Fighting is restricted to two classes, the Two-Weapon Fighting Style given to Fighters and Rangers. Compared to other similar features it is one of the stronger options, at least for tiers 1 & 2. However, other classes that want to use Two-Weapon Fighting have to get it from a feat or multiclass into either Fighter or Ranger, and before Tasha's the only option was multiclassing. Having to Multiclass just to make Two-Weapon Fighting as effective a way of weaponizing your bonus action as other options needlessly limits the kinds of characters that can use this option. Taken as a feat the Two-Weapon Fighting Style just falls short of what is gained by other similar feats, like Crossbow Expert or Polearm Master.
Two-Weapon Fighting lacks competitive features characters can invest in to increase its effectiveness. This is touched on in the previous two points but I think it is worth highlighting on its own. This is the reason why Two-Weapon Fighting goes from being the best option at level 1 to the worst option by levels 2-5 depending on your character. A ranged character with Crossbow Expert can go on to pick up Sharp Shooter, a two hander melee character with Polearm Master can go on to take Great Weapon Master, a one hander melee character with Polearm Master can take the Dueling Fighting Style (If they didn't already have it). Each of these characters already do better damage than the same character would with Dual Wielder using Two-Weapon Fighting and have other ways of enhancing their damage further that is specific to their weapon choices.
(This is a slight exaggeration in the one hander melee case as they need a +4 ability modifier to make up the difference in damage dice compared to Two-Weapon Fighting and Dual Wielder. But once the character has both their respective feat and fighting style the one hander melee character will always do more damage regardless of strength modifier. And this ignores the fact that the one hander melee character has more ways to weaponize their reaction, and with a shield they will also always have a better AC)
With the new playtest these points largely still stand. Polearm Master has now been effectively limited to two-handed weapons by only effecting weapons with the Heavy and Reach properties, so at least one hander melee characters should no longer do more damage than two-weapon melee characters. However, it still means a 2 handed melee character can make just as many attacks as a two-weapon melee character. With the Nick property at least the two-weapon melee character frees up their bonus action, but they have to use one handed melee weapons with smaller damage dice to get that benefit. Also in the playtest Dual Wielder was nerfed to still require that at least one of your weapons have the Light property instead of no longer requiring Light weapons at all. I haven't run the numbers for the playtest but it seems like the 2 handed style will still have a decisive lead but the two-weapon style won't just be bottom of the barrel anymore.
To me the advantage of the two-weapon style should be getting to make more attacks than other styles, but this is a tricky thing to balance. What I would like to see is maybe change the Nick property so that you get an additional attack with your Attack Action and you can make an additional attack with your bonus action. This might be too much and it does double the effectiveness of the Two-Weapon Fighting Style which might make it too powerful.
Also in Playtest 7 did they restrict the Fighting Styles to only classes with that class feature? The reprint of the Fighter's Fighting Style feature seems to suggest classes without the Fighting Style feature can't take Fighting Style feats, but they didn't reprint the Fighting Style feats to reflect this.
Honestly, they should remove polearm mastery, it distorts the entire weapon math. Or add features that are comparably strong for other fighting styles -- non-polearm great weapons, sword and board, dual wielding.
PAM and CBM are both OP feats. Setting aside feats, TWF is an effective option for the classes meant be able to fully utilize it, as I outlined. Fighters have few to no dedicated bonus actions, and while at present Rangers can’t bounce HM between multiple targets while using TWF, it works well if you have a single target to focus on, and they likewise don’t have many class features that call for regular use of the bonus action. Obviously TWF doesn’t work so well on other classes, but by the same token Rangers can’t take the styles that make shields or great weapons most effective. By design, different classes support different weapon arrangements.
Absent feats which are, frankly, balance problems in their own right, basic 2WF is overpowered in tier 1, fairly neutral in tier 2, and underpowered in tier 3-4.
TWF overpowered in tier 1? Hardly the case, strong sure but not overpowered. You do pay a bonus action to get that extra attack and the damage therein. If you compare to a ranger with Hunter's Mark to use that same bonus action and wielding a long bow, you get to deal 1d8 + ASM + 1d6 for an average of 11 damage (ASM = +3). With a heavy crossbow you add +1 damage.
TWF with the fighting style is 2d6 + 2xASM for an average of 13 damage. ASM in tier 1 is max +3 (considering point buy the more balanced version to rolling your stats, which means 15 ability score is max and then you can add racial features to increase your score to 16). The difference for TWF is then a +2 over the Longbow Ranger, who can attack at range, and only +1 over a Heavy Crossbow Ranger.
A Greatsword fighter with GWF (one of the worst fighting styles) is 2d6 + 1xASM with a technical average damage increase of 1.5 (due to the rerolls on 1s and 2s on the damage die) for an average of 11.5 damage.
A Longsword fighter with Duelist fighting style is 1d8 + 1xASM + 2 for an average of 9.5 damage, with the trade-off of +2 AC with a shield.
I don't know how TWF is overpowered in your eyes with these metrics.
I think something that would logically make sense would be to add a +2 to your attack rolls (to-hit) when fighting with 2 weapons. <snip>
Thing is that attack modifiers are seldom the issue when considering the Two-Weapon combat style (you generally get this through the proficiency bonus, ability modifier, magical bonuses and to a degree assisted by advantage on attack - such as through flanking). <snip>
But one of the complaints was about the ability to get two magic weapons. If you get a bonus to hit naturally with TWF, then the magic weapons become less important.
Magic weapons (+ 1 through +3) grants 3 distinct benefits: Bypasses bigger monster's resistance to non-magical damage. It grants a bonus to hit through attack rolls. And it grants a bonus to damage rolls.
The least significant of these benefits is generally the attack bonus. Attack is a metric that doesn't matter once you can generally overcome the opponent's AC. Thus a +5 to attack and a +20 to attack is generally not that different the later into the game you come - it doesn't matter if you overcome the enemy's AC by 1 or 20. However there exists certain feats or class features that trade accuracy for damage or some other benefit. Great Weapon Master and Sharp Shooter being some of the classic examples, so a bonus to attack is useful if you can trade it. This option is not available to one-hander melee weapons - including TWF.
The most impactful of the benefits is the bypassing of monster resistance to non-magical damage. It is widely enough present that it matters for PC level 8+ and it can be useful for earlier encounters.
And you can generally not get enough damage. Because every monster/enemy is mainly scaled with health compared to AC. It is not a great experience to never be able to hit the enemy because their scaling put their AC way above what you're expected to roll for Attack, so you scale monster with HP rather than AC. Thus damage is a coveted stat to gain.
If you look at your suggestion with that in mind, then we're not improving TWF much by giving it a flat bonus to attack rolls. It mainly improves it early game (pre level 5) where TWF is already very strong. This is not a good way to improve on the mechanic. The trouble is scaling damage.
Honestly, they should remove polearm mastery, it distorts the entire weapon math. Or add features that are comparably strong for other fighting styles -- non-polearm great weapons, sword and board, dual wielding.
I don't agree that Polearm Master is the most egregious feat when comparing weapon math, it is more Great Weapon Master which does so.
Edit: I was not aware that PAM could be used with spears and quarterstaffs while wielded in one hand. That makes the feat a lot stronger than I initially perceived and I will then agree with the development change in the playtest to limit it to weapons with the heavy and reach properties - basically only Glaive, Halberd and Pike.
@Fangeye: I like the analysis and agree with the points. I have not followed the playtests so I cannot really say what makes sense when considering those changes.
What do you think of up2ng's suggestion - which I will change slightly below - to add the following to the rules for Two-Weapon Fighting:
"On your turn, whenever you make a weapon attack with a melee weapon with the Light property in one hand, except the first weapon attack you make during that action, you may make a bonus weapon attack with another melee weapon with the Light property wielded in another hand. If you utilize this feature you cannot use a bonus action to make a weapon attack through the rules above during that same action."
This means whenever you gain an extra weapon attack through the Extra Attack feature, you get an extra "off-hand" weapon attack too. This frees up the bonus action and keeps granting bonus "off-hand" attacks to Fighters who scale their Extra Attack feature. The reason I didn't include "Whenever you take the Attack action" was so class features and spells that make weapon attacks could potentially take benefit from it. For instance the Ranger - Hunter's Whirlwind which makes a melee attack against any number of creatures within 5 ft. If you happen to hit 4 targets, then TWF grants you 3 bonus attacks with your "off-hand".
To avoid that any extra actions or bonus attacks (like Opportunity Attacks) would gain 100% benefit from this change, I had to link the first attack exception to the action itself instead of just your turn. Otherwise a Haste'd character could take that Haste-action to make their first weapon attack and effectively double their Attack action's weapon attacks. Otherwise a lvl 5 Fighter could take their attack action and have 2 main-hand attacks and 1 TWF bonus attack and then pop Action Surge to get 2 main-hand attacks and 2 TWF bonus attacks. Action Surge should have the same amount of attacks.
You can always play around with adding modifiers to this feature like a -2 to attack rolls or -1 to damage rolls. Or if you attack with advantage, you wont with the feature or that critical strikes don't double the dice. And that could be for all or just the bonus attacks.
PAM and CBM are both OP feats. Setting aside feats, TWF is an effective option for the classes meant be able to fully utilize it, as I outlined. Fighters have few to no dedicated bonus actions, and while at present Rangers can’t bounce HM between multiple targets while using TWF, it works well if you have a single target to focus on, and they likewise don’t have many class features that call for regular use of the bonus action. Obviously TWF doesn’t work so well on other classes, but by the same token Rangers can’t take the styles that make shields or great weapons most effective. By design, different classes support different weapon arrangements.
Fighters and Rangers don't utilize their bonus action?
Fighter:
Uses it for Second Wind
Subclasses
Arcane Archer doesn't make sense for TWF
Banneret doesn't use BAs
Battle Master (uses it in a couple of major Maneuvers from the class feature, like Feinting Strike and Grappling Strike)
Cavalier uses it for riposting against marked enemies hitting allies
Champion doesn't use BAs (they are all passives)
Echo Knight uses it as its main gimmick with their echo
Eldritch Knight uses it when casting a cantrip to get a weapon attack
Psi Warrior uses it sparingly to recover psi dice or for utility
Rune Knight uses it to grow in size (the main reason for the class) and occasionally to invoke their runes
Samurai uses it to gain advantage on all weapon attacks during this turn and some temp HP (again a main benefit to that subclass)
Ranger:
Uses their BA for casting and repositioning Hunter's Mark
Uses it to Hide from lvl 14 for the Unseen Attacker advantage to hit and disadvantage to be hit, which generally only works for ranged Rangers
Subclasses
Beastmaster uses it to direct their companion to attack (main feature)
Drakewarden uses it to direct their drake to attack (main feature)
Feywanderer technically doesn't use their BA before lvl 15 (to cast Misty Step) but they do want to spell cast, which clashes with the two weapons in hand of TWF and the Somatic component of spell casting (and also the Material) and most importantly their 3rd level class feature is a bonus damage proc once per turn per creature - which is way easier to ensure multiple procs per turn with a ranged weapon, than with TWF in melee range. Granted it either has to be past level 5 or with the Crossbow Expert feat (which is technically ranged TWF)
Gloom Stalker's ambush grants an additional weapon attack, judge for yourself if you want a 1d6, 1d8, 1d10, 1d12 or 2d6 weapon attack.
Horizon Walker locks their BA for force damage conversion +1d8/2d8 damage for one attack (well mostly first when you hit that 2d8 damage die on lvl 11 or you hit opponents with physical damage resistances)
Hunter doesn't technically mind, but some of their class features are so so much stronger with a non-TWF build
Monster Slayer uses their BA to designate targets for 1d6 bonus damage once per turn (basically a free Hunter's Mark that only procs once per turn)
Swarmkeeper generally has benefits to kite targets (or technically chase) and use their BA on occasion to gain short range flying (10 ft.) - again something that seems more useful to a ranged character than a TWF.
I would say that most subclasses uses their BA as either an integral part of their rotation or for occasional benefit, enough so that locking your BA to TWF or having to forego the TWF BA attack is a significant cost.
Using a bonus action for a one-off feature or mode activation doesn’t override TWF; those uses are typically quite finite and unlikely to be used more than once in a fight. I’ve seen a TWF Rune Knight, for example, and trust me he was using his Bonus Action to attack far more than he used it for anything else. Cavalier‘s use is so situational that I’d rather plan on mostly using TWF; Samurai get three uses a day for most of their progression; honestly for EK I’m not sure how much they use cantrips over weapons (broadly speaking the numbers favor weapons); I expect typically a Psi Warrior would regain their one die between encounters rather than wait until they’re empty, and regardless it’s also a one-off; Echo Knight is yet again one you proc at the start of the fight, with the extra attack from it not using the BA; Battlemaster is really too variable to summarize one way or the other.
Regarding Rangers, I specifically addressed HM and how it synergizes with TWF unless you’re fighting a mob of weak creatures, which also covers Monster Slayer. Swarmkeeper is once again a one-off you proc at the start of the fight, not a constant button. Horizon Walker is really in the same boat as bouncing HM; it’s ~4 extra damage on your first hit or ~6-8 extra damage if you land all three. Neither one truly invalidates the other simply by existing, it’s a case of choosing the right tool for the job. Now, pet classes I will grant lock down the bonus action at present, but they’re looking like the exception, not the rule.
Also, I’m not arguing that TWF is an optimum arrangement, because I find focusing on optimization in RPGs to be unspeakably dull and narrow. My point is that the action economy works out, albeit occasionally it does call for some critical thinking.
Fighters and Rangers don't utilize their bonus action?
<snip>
I would say that most subclasses uses their BA as either an integral part of their rotation or for occasional benefit, enough so that locking your BA to TWF or having to forego the TWF BA attack is a significant cost.
For the Fighters, you won't be able to Grappling Strike while wielding two weapons anyway as you need a free hand, it doesn't make much sense for a Eldritch Knight or Echo Knight (Echo Knight gets you a way to get an additional attack anyway). You only need to grow in size once as a Rune Knight, then the rest of your turns you have a free BA for anything.
It actually works really well for a Battle Master, as it gives you more opportunities to use your Maneuvers.
True, Grappling Strike with TWF doesn't make sense, but it was a use of a bonus action so I included it along Feinting Strike.
Due to Eldritch Knight's version being different than the Wizard - Bladesinging's version (basically the same concept, trading a weapon attack for a cantrip), then yes TWF on EK is definitely a lot worse. It also costs the Eldritch Knight a bonus action while being free for the Bladesinger atop that the EK has to first use a cantrip (often used to cast Booming Blade or Green-Flame Blade), before the weapon swing and that it requires a spell cast action instead of being a part of the attack action, waving goodbye to the Fighter's upgraded version of Extra Attack feature. Yeah the EK is not particularly well put together on a Fighter class, but it does offer some half-decent options. However an EK can still cast Spirit Shroud from level 14 (yeah, yikes) and would then have benefit from TWF. Additionally you can bond with a weapon with the thrown property, throw it during your attack action, return it with a bonus action, then throw it again - possibly to take advantage of the level 10 class feature to have enemies hit by a weapon attack to have disadvantage on saving throws against a spell you cast before the end of your next turn. Additionally if TWF doesn't cost a bonus action, you can gain one extra attack here in melee (or throw it if you dual wield thrown weapons).
Most encounters are "scheduled" to take 3-5 turns. Using one to enlarge, cast echo (or any other buff-up like Hunter's Mark) and forego half or near half your damage output, when any other combat style - two-hander, sword-and-board, duelist, archer or mage don't have that same handicap, just makes TWF a poor choice in comparison.
Battle Master starts off with 4 superiority dice, so burning half in the first turn is unlikely your preferred combat choice, but there's always Action Surge if that is your desire. Additionally if your aim is to gain an attack bonus, you need to empower two weapon attacks compared to a two-hander. Basically due to limits you'd often rather want a few meaty swings on a Battle Master than many smaller attacks. This line of argument basically is the same as TWF being great for Paladin for being able to use Divine Smite more frequently. That is often not the problem compared to the cap on how much you can do it. Again we have the disparity that a weapon swing is not equal when comparing a two-hander and a TWF (one-hand Duelist is similar to a two-hander), and in 5e there's many ways to perform a weapon swing - favoring a non-TWF style. And this basically applies to any class feature granting bonus attacks - like the one from Echo Knight.
TWF costing a bonus action is definitely part of why it is considered bad for many subclasses, including Fighter and Ranger. Having some way to remove that cost would go a long way to make it more comparable to a two-hander.
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Just for posterity, lets look at your TWF Rune Knight, comparing to a two-hander Greatsword Rune Knight. Both having their respective fighting style.
Turn 1
TFW: casts enlarge, swings once for 1d6 + 1d4 + 3 (ASM) = 9 average damage
Two-hander: casts enlarge, swings once for 2d6 + 1d4 + 3 (ASM) + 2x0.66 (the average damage die improvement on a d6 with GWF) + 1x0.5 (d4 GWF) = 14.33 average damage
Turn 2
TWF: swings twice for 2d6 + 2d4 + 2x3 = 18 average damage
Two-hander: swings once, no change = 14.33 average damage
From level 1 till 4, the 2-hander wins turn 1. It's equal (27 vs 28.66) on turn 2. From turn 3 the TWF deals more damage.
If the TWF RK ignores Enlarge they deal 2d6 + 2x3 = 13 damage per turn, forever lacking behind.
At level 5 we get the Extra Attack feature (and lets say ASM = +4):
Turn 1
TWF: Casts enlarge, swings twice for 2d6 + 2d4 + 2x4 = 20 average damage
Two-hander: casts enlarge, swings twice for 4d6 + 2d4 + 2x4 + 4x0,66 + 2x0,5 = 30.64 average damage
Turn 2
TWF: swings thrice for 3d6 + 3d4 + 3x4 = 30 average damage
Two-hander: swings twice, no change = 30.64 average damage.
The two-hander is always ahead of the TWF, and they still have their BA to use as they like. If they pick up GWM (forgetting the trade of attack for damage) you can use a BA to get another attack if you get a crit or a kill during your turn, which is not unlikely to achieve once per encounter.
As I said before, this isn't about optimization, because D&D isn't an MMO and you're not going to get kicked from the raid for dealing less than the absolute max damage possible. Plus your math doesn't account for additional critical hit opportunities, and you did the math wrong for a Rune Knight. They get 1 extra d6 per round, they don't cast Enlarge.
As I said before, this isn't about optimization, because D&D isn't an MMO and you're not going to get kicked from the raid for dealing less than the absolute max damage possible.
This argument should really be used less, and/or used properly, because it's not an argument for 2WF being UP (or OP, or anything else), it's an argument for not caring whether it's UP. That's a legitimate argument... but it's not the same argument.
As I said before, this isn't about optimization, because D&D isn't an MMO and you're not going to get kicked from the raid for dealing less than the absolute max damage possible.
This argument should really be used less, and/or used properly, because it's not an argument for 2WF being UP (or OP, or anything else), it's an argument for not caring whether it's UP. That's a legitimate argument... but it's not the same argument.
My initial argument was that there isn't truly that much competition for the BA slot on Fighters and Rangers, which was then segued into a stats based argument. I'm pointing out that stats are not relevant to my initial point.
The big problem with trying to compare two weapon fighting with great weapon fighting is that almost all two weapon fighters are dex primary, and there aren't any two-handed finesse weapons. It's very unlikely for a ranger to do more damage with a rapier than with two shortswords, though a fighter might.
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I started another thread about the Extra Attack feature stacking for Two-Weapon Fighting to give the mechanic a boost as the mechanic is generally considered weak in 5e. However I have since come to the conclusion that that was not the best way to go about improving Two-Weapon Fighting. Instead of continuing a discussion on Two-Weapon Fighting in a thread unrelated by name, I decided to start this thread up.
To start up the discussion I think we need to understand why the mechanic is considered poor by many - even a majority I believe.
Pros:
Cons:
With the Fighting Style you generally see a damage advantage over a standard two-hander like the Greatsword's 2d6. As soon as you hit level 5 and get the Extra Attack feature, the advantage is gone. And from thereon it only gets worse for the TWF.
With a plethora of drawbacks, mainly stemmed in action economy and damage scaling, it would seem that Two-Weapon Fighting is not a great combat style for the general adventurer. So this thread is to explore some changes to existing rules, or additional rules, or new feats (investment options). Technically it could also be something like minor or moderate properties for magic items.
Do you have any ideas on how to improve Two-Weapon Fighting?
We already had some ideas from the previous thread that I will post here:
The original idea of the previous thread I posted was to allow the Extra Attack feature to stack when used with Two-Weapon Fighting. Thus if you acquire the Extra Attack feature from say a level 5 Fighter and a level 5 Paladin, you could stack them. It would only work when you were using your Bonus Action to make an attack through the Two-Weapon Fighting rules and you would have to attack twice with each weapon. I came to a rough ruleset that would be put into the PHB under chapter 9 about Two-Weapon Fighting with the following text:
"If you have two instances of features or abilities that grant extra attacks when taking the Attack action, like the Extra Attack feature, Warlock's eldritch invocation Thirsting Blade, Tenser's Transformation, etc. you can instead use your bonus action to attack twice with the weapon in your other hand when using Two-Weapon Fighting unless you have already attacked with that weapon during this Attack action. You cannot attack with that weapon further during this Attack action. You ignore these limitations if you make or made attacks with that weapon during a separate action - like the additional action gained from the Haste spell."
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Another idea posted in the thread was a Great Weapon Master equivalent feat:
And similarly was suggested the Homebrew: Light Weapon Master
Both are basically variants of the Great Weapon Master feat. Personally I found that making a GWM variant would be uninteresting and wouldn't set two-hander combat styles apart from two-weapon fighters. And you run the risk of the TWF variant being the better damage option that overshadows GWM.
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Another idea was to remove the Bonus Action cost to Two-Weapon Fighting if you have the Extra Attack feature (or equivalent). Evening out the playing field against a two-hander like a Greatsword, dealing roughly the same damage and without costing the TWF their Bonus Action for no apparent gain. Greatsword with their 4d6 + 2xASM (ability score modifier) and the TWF with 3d6 + 3xASM - at level 5 ASM is assumed to be a +3.
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I brainstormed a handful of bulletins that could be used for making new feats:
I'll take another crack at this one.
First, in my opinion if we are trying to improve the general concept of Two-Weapon Fighting which is a core rule / mechanic for combat from the PHB Chapter 9, then the solution should not be to add a feat that creates better balance. Remember, Feats are technically optional rules according to the books. Core mechanics should be balanced assuming a game where the DM does not allow feats. If some feats currently exist which makes one type of build more powerful than another then that is a separate issue of the balance and quality of the Feats which have been officially published so far -- for our purposes here I believe that the existing feats should generally be ignored.
Here is my current solution which is somewhat simplistic (in keeping with the general 5e design choice of higher simplicity and less granularity) and is probably overpowered:
...
Two-Weapon Fighting
When you take the Attack action and attack with a light melee weapon that you're holding in one hand, you can use a bonus action to attack with a different light melee weapon that you're holding in the other hand. You don't add your ability modifier to the damage of the bonus attack, unless that modifier is negative.
If either weapon has the thrown property, you can throw the weapon, instead of making a melee attack with it.
If your Attack action allows for more than one attack and you make all of those attacks with a light melee weapon that you're holding in one hand, then in-between each of those attacks you can make one additional attack with a different light melee weapon that you're holding in the other hand. You don't add your ability modifier to the damage of the additional attacks, unless that modifier is negative.
...
As a Fighter makes progress, this would allow for the option to make the following attacks:
attack, off-hand bonus action attack
attack, off-hand attack, attack, off-hand bonus action attack
attack, off-hand attack, attack, off-hand attack, attack, off-hand bonus action attack
attack, off-hand attack, attack, off-hand attack, attack, off-hand attack, attack, off-hand bonus action attack
Like I said, this is probably too much. I considered tacking on a statement to the end such as the following: "For every additional attack taken your AC is reduced by 1 until the start of your next turn." But I'm not convinced that such a tradeoff makes sense thematically.
It is mostly considered "weak" in the context of feats like great weapon master, polearm master, cross bow expert and sharpshooter. Two weapon fighting doesn't have a feat that gives a comparable boost to damage as great weapon master or sharpshooter. If you compare two weapon fighting with two short swords and the fighting style vs a long sword and shield with the fighting style then the damage comparison is more reasonable.
longsword = 4.5+2 = 6.5 +stat
Short sword = 3.5 +stat
Short Sword off hand = 3.5 + stat
Two weapon fighting is 7 + 2 x stat vs 6.5 + stat in tier 1 for a fighter. Tier 2 this becomes 13 + 2 * stat vs 10.5 + 3 x stat .. for a 16 stat this is 19 vs 19.5 for 18 stat it is 21 vs 22.5 at the expense of 2 AC due to the lack of a shield.
Comparing to a greatsword ... the numbers are 8.5 + stat (GWF adds about 1.5) vs 7 + 2 x stat in tier 1 and 17 + 2 x stat vs 10.5 + 3 x stat. However, the TWF gives two chances to hit, meaning more opportunities to smite or sneak attack.
Basically, TWF isn't that far off the baseline of other attack options for martial classes. The real difference shows up when you start comparing feats that increase damage or provide additional attacks ... while TWF has the lackluster dual wielder feat increasing AC by 1 and allowing the character to use weapons that aren't light ... which amounts to a +2 increase in damage in tier 1 and +3 in tier 2 (1 point/attack due to using a d8 weapon instead of a d6 and a slightly better AC).
If you want to improve TWF, then I'd suggest looking at adding a feat that boosts damage and reduces to hit comparably to GWM/SS. Maybe something like Decisive Flurry -3 to hit and +5 to damage for each weapon attack while dual wielding. (Need to do the math to get the appropriate modifiers).
The lackluster feats that can be used by TWF is definitely a source of weakness for the combat style. However I would go more basic and say that using the combat style costs you your bonus action. In the early stages, that translates to a slight damage advantage, so it has a trade-off (you pay the cost and reap the benefit). At level 5 with the Extra Attack feature, that advantage is nullified against a two-hander (the most comparable combat style because it also focuses primarily on damage) and also against a single one-handed weapon with the Duelist fighting style - just like you described. However the two latter do not have the cost of a bonus action and neither do they carry the baggage of opportunity costs that TWF does (see the OP's con list).
So TWF is somewhat comparable in damage to other combat style when taking your first attack action on each of your turns. However as soon as we start counting Opportunity Attacks, class feature bonus attacks, additional actions (like from Haste) the cracks starts becoming very visible. This is the disparity about weapon attack value. That is much lower for TWF than they are for basically any other combat style. And TWF has basically nothing to show for it.
A GWM variant is likely the easiest solution to make it more comparable (in terms of investment output). However that is also the least interesting solution and doesn't do much to separate TWF from a two-hander combat style.
That's why one of the bulletins I brainstormed for a new feat was to utilize the same idea as GWM/SS - sacrifice accuracy for more damage, but then link it to your proficiency bonus and instead of -1 accuracy for +2 damage, it is 1-to-1. However to not just have a much worse GWM you could select how much you sacrifice, instead of being an on/off switch like GWM/SS. This means you wont get as much damage out of it, but you're more likely to actually apply the damage because you can more easily find a sweetspot where you can hit the enemy. This also means you can effectively pick it up earlier because the entrance penalty is not as steep as GWM. The feat would then also scale with your character level and proficiency is capped at +6 so it will never be a stronger damage option than GWM.
The neat part is that it could easily be used for one-handers (sword-and-board or duelist builds) too, but it still provides more benefit/opportunity for a TWF build. The broader you can make these feats without sacrificing reason or the intended use the better.
I would then suggest for this particular feat to also have some additional utility. One of which could be some additional benefit to Opportunity Attacks, Disengage actions or whatever.
Thing is that attack modifiers are seldom the issue when considering the Two-Weapon combat style (you generally get this through the proficiency bonus, ability modifier, magical bonuses and to a degree assisted by advantage on attack - such as through flanking). The problem for TWF is mostly damage/utility and particularly in the later stages of the game basically level 5+. While I agree that feinting and basically better ability to manipulate your opponent and their weapon is thematically a part of fighting with two weapons, however this design space is already being used by the Fighter's subclass Battle Master and its Maneuver class feature. So utilizing it for TWF should be handled delicately if at all.
I kinda like this version. I'm not sold that this should be usable alongside the bonus action attack from standard TWF. 4 attacks at level 5 seems a bit... much. I would rather that it is an alternate use of TWF - basically granting each Extra Attack bonus an additional off-hand weapon attack for free (non-stacking - the Fighter's version don't stack but upgrade).
At Fighter level 11 this would result in a TWF having 3 main-hand weapon attacks and 2 off-hand weapon attacks for 5d6 + 5xASM,
whereas a two-hander would have 3 weapon attacks for 6d6 + 3xASM.
This would have TWF have a slight damage advantage over a two-hander naturally for the attack action. However the two-hander has an advantage for Opportunity Attacks, extra actions/attacks and obviously still has GWM to bolster their damage output.
I will add additional comments in a later reply.
Two weapon fighting has problematic level scaling. Absent feats which are, frankly, balance problems in their own right, basic 2WF is overpowered in tier 1, fairly neutral in tier 2, and underpowered in tier 3-4.
Are we talking in terms of damage die for underpowered? Because imo the difference there is marginal. By the time you’re into tier 3, the average of up to 3 extra comparing a d6 to d12 is marginal, as almost no class or subclass is relying on straight weapon rolls at that point. The action economy issue assumes the class in question has a better use for the BA. Fighters rarely have a dedicated bonus action, and with Rangers it more comes down to tactics; if you’re expecting to bounce between targets, it’s arguably better to save the spell slot; a potential extra 2d6 is about the same value as 1d6+mod. Rogues have a larger suite of potential options, but having to decide between doubling down to attack or retreat is just a reasonable tactical balance, imo. Plus TWF on a Rogue is mostly just fishing for a second chance to proc Sneak Attack if your first attack misses. In all, no one seems particularly crippled by spending a Bonus Action on TWF.
Here are the three core problems I see with Two-Weapon Fighting in 5e:
(This is a slight exaggeration in the one hander melee case as they need a +4 ability modifier to make up the difference in damage dice compared to Two-Weapon Fighting and Dual Wielder. But once the character has both their respective feat and fighting style the one hander melee character will always do more damage regardless of strength modifier. And this ignores the fact that the one hander melee character has more ways to weaponize their reaction, and with a shield they will also always have a better AC)
With the new playtest these points largely still stand. Polearm Master has now been effectively limited to two-handed weapons by only effecting weapons with the Heavy and Reach properties, so at least one hander melee characters should no longer do more damage than two-weapon melee characters. However, it still means a 2 handed melee character can make just as many attacks as a two-weapon melee character. With the Nick property at least the two-weapon melee character frees up their bonus action, but they have to use one handed melee weapons with smaller damage dice to get that benefit. Also in the playtest Dual Wielder was nerfed to still require that at least one of your weapons have the Light property instead of no longer requiring Light weapons at all. I haven't run the numbers for the playtest but it seems like the 2 handed style will still have a decisive lead but the two-weapon style won't just be bottom of the barrel anymore.
To me the advantage of the two-weapon style should be getting to make more attacks than other styles, but this is a tricky thing to balance. What I would like to see is maybe change the Nick property so that you get an additional attack with your Attack Action and you can make an additional attack with your bonus action. This might be too much and it does double the effectiveness of the Two-Weapon Fighting Style which might make it too powerful.
Also in Playtest 7 did they restrict the Fighting Styles to only classes with that class feature? The reprint of the Fighter's Fighting Style feature seems to suggest classes without the Fighting Style feature can't take Fighting Style feats, but they didn't reprint the Fighting Style feats to reflect this.
Honestly, they should remove polearm mastery, it distorts the entire weapon math. Or add features that are comparably strong for other fighting styles -- non-polearm great weapons, sword and board, dual wielding.
PAM and CBM are both OP feats. Setting aside feats, TWF is an effective option for the classes meant be able to fully utilize it, as I outlined. Fighters have few to no dedicated bonus actions, and while at present Rangers can’t bounce HM between multiple targets while using TWF, it works well if you have a single target to focus on, and they likewise don’t have many class features that call for regular use of the bonus action. Obviously TWF doesn’t work so well on other classes, but by the same token Rangers can’t take the styles that make shields or great weapons most effective. By design, different classes support different weapon arrangements.
TWF overpowered in tier 1? Hardly the case, strong sure but not overpowered. You do pay a bonus action to get that extra attack and the damage therein. If you compare to a ranger with Hunter's Mark to use that same bonus action and wielding a long bow, you get to deal 1d8 + ASM + 1d6 for an average of 11 damage (ASM = +3). With a heavy crossbow you add +1 damage.
TWF with the fighting style is 2d6 + 2xASM for an average of 13 damage. ASM in tier 1 is max +3 (considering point buy the more balanced version to rolling your stats, which means 15 ability score is max and then you can add racial features to increase your score to 16). The difference for TWF is then a +2 over the Longbow Ranger, who can attack at range, and only +1 over a Heavy Crossbow Ranger.
A Greatsword fighter with GWF (one of the worst fighting styles) is 2d6 + 1xASM with a technical average damage increase of 1.5 (due to the rerolls on 1s and 2s on the damage die) for an average of 11.5 damage.
A Longsword fighter with Duelist fighting style is 1d8 + 1xASM + 2 for an average of 9.5 damage, with the trade-off of +2 AC with a shield.
I don't know how TWF is overpowered in your eyes with these metrics.
Magic weapons (+ 1 through +3) grants 3 distinct benefits: Bypasses bigger monster's resistance to non-magical damage. It grants a bonus to hit through attack rolls. And it grants a bonus to damage rolls.
The least significant of these benefits is generally the attack bonus. Attack is a metric that doesn't matter once you can generally overcome the opponent's AC. Thus a +5 to attack and a +20 to attack is generally not that different the later into the game you come - it doesn't matter if you overcome the enemy's AC by 1 or 20. However there exists certain feats or class features that trade accuracy for damage or some other benefit. Great Weapon Master and Sharp Shooter being some of the classic examples, so a bonus to attack is useful if you can trade it. This option is not available to one-hander melee weapons - including TWF.
The most impactful of the benefits is the bypassing of monster resistance to non-magical damage. It is widely enough present that it matters for PC level 8+ and it can be useful for earlier encounters.
And you can generally not get enough damage. Because every monster/enemy is mainly scaled with health compared to AC. It is not a great experience to never be able to hit the enemy because their scaling put their AC way above what you're expected to roll for Attack, so you scale monster with HP rather than AC. Thus damage is a coveted stat to gain.
If you look at your suggestion with that in mind, then we're not improving TWF much by giving it a flat bonus to attack rolls. It mainly improves it early game (pre level 5) where TWF is already very strong. This is not a good way to improve on the mechanic. The trouble is scaling damage.
I don't agree that Polearm Master is the most egregious feat when comparing weapon math, it is more Great Weapon Master which does so.
Edit: I was not aware that PAM could be used with spears and quarterstaffs while wielded in one hand. That makes the feat a lot stronger than I initially perceived and I will then agree with the development change in the playtest to limit it to weapons with the heavy and reach properties - basically only Glaive, Halberd and Pike.
@Fangeye: I like the analysis and agree with the points. I have not followed the playtests so I cannot really say what makes sense when considering those changes.
What do you think of up2ng's suggestion - which I will change slightly below - to add the following to the rules for Two-Weapon Fighting:
"On your turn, whenever you make a weapon attack with a melee weapon with the Light property in one hand, except the first weapon attack you make during that action, you may make a bonus weapon attack with another melee weapon with the Light property wielded in another hand. If you utilize this feature you cannot use a bonus action to make a weapon attack through the rules above during that same action."
This means whenever you gain an extra weapon attack through the Extra Attack feature, you get an extra "off-hand" weapon attack too. This frees up the bonus action and keeps granting bonus "off-hand" attacks to Fighters who scale their Extra Attack feature. The reason I didn't include "Whenever you take the Attack action" was so class features and spells that make weapon attacks could potentially take benefit from it. For instance the Ranger - Hunter's Whirlwind which makes a melee attack against any number of creatures within 5 ft. If you happen to hit 4 targets, then TWF grants you 3 bonus attacks with your "off-hand".
To avoid that any extra actions or bonus attacks (like Opportunity Attacks) would gain 100% benefit from this change, I had to link the first attack exception to the action itself instead of just your turn. Otherwise a Haste'd character could take that Haste-action to make their first weapon attack and effectively double their Attack action's weapon attacks. Otherwise a lvl 5 Fighter could take their attack action and have 2 main-hand attacks and 1 TWF bonus attack and then pop Action Surge to get 2 main-hand attacks and 2 TWF bonus attacks. Action Surge should have the same amount of attacks.
You can always play around with adding modifiers to this feature like a -2 to attack rolls or -1 to damage rolls. Or if you attack with advantage, you wont with the feature or that critical strikes don't double the dice. And that could be for all or just the bonus attacks.
Fighters and Rangers don't utilize their bonus action?
Fighter:
Ranger:
I would say that most subclasses uses their BA as either an integral part of their rotation or for occasional benefit, enough so that locking your BA to TWF or having to forego the TWF BA attack is a significant cost.
Using a bonus action for a one-off feature or mode activation doesn’t override TWF; those uses are typically quite finite and unlikely to be used more than once in a fight. I’ve seen a TWF Rune Knight, for example, and trust me he was using his Bonus Action to attack far more than he used it for anything else. Cavalier‘s use is so situational that I’d rather plan on mostly using TWF; Samurai get three uses a day for most of their progression; honestly for EK I’m not sure how much they use cantrips over weapons (broadly speaking the numbers favor weapons); I expect typically a Psi Warrior would regain their one die between encounters rather than wait until they’re empty, and regardless it’s also a one-off; Echo Knight is yet again one you proc at the start of the fight, with the extra attack from it not using the BA; Battlemaster is really too variable to summarize one way or the other.
Regarding Rangers, I specifically addressed HM and how it synergizes with TWF unless you’re fighting a mob of weak creatures, which also covers Monster Slayer. Swarmkeeper is once again a one-off you proc at the start of the fight, not a constant button. Horizon Walker is really in the same boat as bouncing HM; it’s ~4 extra damage on your first hit or ~6-8 extra damage if you land all three. Neither one truly invalidates the other simply by existing, it’s a case of choosing the right tool for the job. Now, pet classes I will grant lock down the bonus action at present, but they’re looking like the exception, not the rule.
Also, I’m not arguing that TWF is an optimum arrangement, because I find focusing on optimization in RPGs to be unspeakably dull and narrow. My point is that the action economy works out, albeit occasionally it does call for some critical thinking.
True, Grappling Strike with TWF doesn't make sense, but it was a use of a bonus action so I included it along Feinting Strike.
Due to Eldritch Knight's version being different than the Wizard - Bladesinging's version (basically the same concept, trading a weapon attack for a cantrip), then yes TWF on EK is definitely a lot worse. It also costs the Eldritch Knight a bonus action while being free for the Bladesinger atop that the EK has to first use a cantrip (often used to cast Booming Blade or Green-Flame Blade), before the weapon swing and that it requires a spell cast action instead of being a part of the attack action, waving goodbye to the Fighter's upgraded version of Extra Attack feature. Yeah the EK is not particularly well put together on a Fighter class, but it does offer some half-decent options.
However an EK can still cast Spirit Shroud from level 14 (yeah, yikes) and would then have benefit from TWF. Additionally you can bond with a weapon with the thrown property, throw it during your attack action, return it with a bonus action, then throw it again - possibly to take advantage of the level 10 class feature to have enemies hit by a weapon attack to have disadvantage on saving throws against a spell you cast before the end of your next turn. Additionally if TWF doesn't cost a bonus action, you can gain one extra attack here in melee (or throw it if you dual wield thrown weapons).
Most encounters are "scheduled" to take 3-5 turns. Using one to enlarge, cast echo (or any other buff-up like Hunter's Mark) and forego half or near half your damage output, when any other combat style - two-hander, sword-and-board, duelist, archer or mage don't have that same handicap, just makes TWF a poor choice in comparison.
Battle Master starts off with 4 superiority dice, so burning half in the first turn is unlikely your preferred combat choice, but there's always Action Surge if that is your desire. Additionally if your aim is to gain an attack bonus, you need to empower two weapon attacks compared to a two-hander.
Basically due to limits you'd often rather want a few meaty swings on a Battle Master than many smaller attacks.
This line of argument basically is the same as TWF being great for Paladin for being able to use Divine Smite more frequently. That is often not the problem compared to the cap on how much you can do it.
Again we have the disparity that a weapon swing is not equal when comparing a two-hander and a TWF (one-hand Duelist is similar to a two-hander), and in 5e there's many ways to perform a weapon swing - favoring a non-TWF style. And this basically applies to any class feature granting bonus attacks - like the one from Echo Knight.
TWF costing a bonus action is definitely part of why it is considered bad for many subclasses, including Fighter and Ranger. Having some way to remove that cost would go a long way to make it more comparable to a two-hander.
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Just for posterity, lets look at your TWF Rune Knight, comparing to a two-hander Greatsword Rune Knight. Both having their respective fighting style.
From level 1 till 4, the 2-hander wins turn 1. It's equal (27 vs 28.66) on turn 2. From turn 3 the TWF deals more damage.
If the TWF RK ignores Enlarge they deal 2d6 + 2x3 = 13 damage per turn, forever lacking behind.
At level 5 we get the Extra Attack feature (and lets say ASM = +4):
The two-hander is always ahead of the TWF, and they still have their BA to use as they like. If they pick up GWM (forgetting the trade of attack for damage) you can use a BA to get another attack if you get a crit or a kill during your turn, which is not unlikely to achieve once per encounter.
As I said before, this isn't about optimization, because D&D isn't an MMO and you're not going to get kicked from the raid for dealing less than the absolute max damage possible. Plus your math doesn't account for additional critical hit opportunities, and you did the math wrong for a Rune Knight. They get 1 extra d6 per round, they don't cast Enlarge.
This argument should really be used less, and/or used properly, because it's not an argument for 2WF being UP (or OP, or anything else), it's an argument for not caring whether it's UP. That's a legitimate argument... but it's not the same argument.
My initial argument was that there isn't truly that much competition for the BA slot on Fighters and Rangers, which was then segued into a stats based argument. I'm pointing out that stats are not relevant to my initial point.
The big problem with trying to compare two weapon fighting with great weapon fighting is that almost all two weapon fighters are dex primary, and there aren't any two-handed finesse weapons. It's very unlikely for a ranger to do more damage with a rapier than with two shortswords, though a fighter might.