Simple, sweet, and powerful. Adding your primary ability modifier to your initiative greatly increases your impact on each battle. As a full caster with access to your wizard spell list, the earlier you can cast a spell the better. Best case scenario you have the ability to shut down encounters before the enemy can even move, even at low levels. Worst case scenario, you’re probably not acting last in any encounter, and if you find yourself surprised you are highly likely to have your turn and become “unsurprised” before your foes can take full advantage of the situation. After your first surprised turn is over you have access to your reaction spells and abilities.

there is a point where investment into initiative gives diminished returns. 7-12 seems to be a sweet spot. There are only a handful of creatures that have dexterity modifiers of +4 or higher. There are even fewer creatures that receive other initiative bonuses. The war wizard easily lands in this threshold.

A well known and low level feature for the war mage. As a reaction you can gain +2 AC vs a confirmed hit or +4 to a saving throw you already know you failed. This can be attractive to many multiclass builds. The small AC bonus is decent, but the save bonus is particularly powerful as you get to know you failed the save before you use the feature. This means you’re much less likely to “waste” the reaction. It’s also attractive since it costs no resources, and the leveled spellcasting restrictions may not hinder your build at all.

  The big issue is that when this feature is used, it locks out the characters ability to cast spells of 1st level or higher until the end of its next turn. This may heavily impact a player that further invests into this wizard subclass. An important point is that though use of this feature heavily restricts your spellcasting, it does not stop you from making use of spells you have already cast that may give  new actions or bonus actions temporarily. This also makes spells that last longer than 1 round more appealing, as you have to plan around the penalty of loosing your spellcasting feature for a round. Your available reactions need to be considered at this point too. The shield and absorb elements spells need to be carefully weighed against your arcane deflection feature for when best to make use of them, as you only get one reaction a turn. A 2nd level war wizard has a maximum of 4 spell slots per long rest, and a +2 AC bonus may at times prove more beneficial than using a shield spell, especially at these lower levels where the creatures your fighting are likely to have lower to hit bonuses. Without investment into AC from some source, this quickly becomes an ability used only for the save bonus for a wizard, until level 14 when you may want to use the bonus damages granted by this reaction.

  Tactical wits initiative bonus and the arcane deflection feature work together to reward a specific gameplay experience, but the further your gameplay deviates from this style,  the more the features feel restrictive and work against you.

  Tactical wit looks like a boost at first glance, but it’s more a necessary boost to supplement arcane deflection than a stand alone initiative increase. Your high initiative drastically increases the likelihood that you can cast your leveled spells on your first turn. So, before other creatures have had their turn, your wizard needs to survey the battlefield and attempt to choose the best spell they can for that encounter since this may be the only time the entire encounter they can cast leveled spells. Enemies bunched up, walls and control effects like storm sphere or wall of force. Many enemies scattered, perhaps a defensive buff like mirror image. An enemy caster in the ranks? Casting greater invisibility on yourself to drastically increase your defenses against the minions while limiting their spell options targeting against you, especially counterspell. Enemies too strong for an AOE to be effective along with casters present? Throw down a sleet storm to even the playing field or allow your party to leave. Early/weaker encounter perhaps in confined spaces? you can conserve slots and cast a flaming sphere or similar spell.

A feature that is often hand waved as weak due to its lack of impact when gained. Power surge has several key points that need to be understood individually before they can be effectively used.

1. Power surge has very particular wording that limits its use to once per turn, but not your turn. This means spell effects that can deal damage on other creatures turns can be used to surge multiple times in one round.
2. Power surges extra damage can only be applied to a single creature per use, even if the spell is an AOE.
3. Power surge is a flat damage increase, this means that it increases the minimum and maximum damage done, not just sliding the average damage up by re-rolling die.
4. Power surges damage type is force so the small surge damages bypass most resistance and immunities.
5. The maximum surges you can store is equal to your modifier, likely a +3 to +5.
6. You generate a power surge when you successfully counterspell a spell or use dispel magic to end spells. Dispel magic can end multiple spells with a single cast, and the level of the spell can led in these ways is not capped. This means cantrips are valid targets to generate surges.
7. While most spells require sight of a target to take effect, power surge does not.
8. while the damage is based on wizard levels, the spells themselves don’t have to be wizard spells or even rely on intelligence directly. The number of maximum uses is tied to intelligence though.
9. Power surge can boost the damage of any spell cast that deals damage regardless of school, unlike the evoker.
10. power surge scales up in power quickly and reliably without the need for feat investment.
11. power surge let’s you partially use of the spell slot you sacrificed To add to damage when arcane deflection otherwise cuts you away from leveled casting.

Taking all these points into account, the feature is similar in nature to a wizard version of the empowered spell metamagic feature. The caveats being that it takes more effort/time to build power surges and that it’s single target in effect. When the feature is gained at level 6 you may potentially have a +4 modifier to your intelligence, but you are very limited in spell slots and cantrips to make use of your dispel feature. Until level 10-12 you are limited to only building charges by occasionally counterspelling or successfully resting. Level 10-12 is the breakpoint for you to consider spending a 3rd level spell to dispel the combined effects of cantrips and rituals on a target to gain a total of 5 power surges if you deem necessary. This is because your Intelligence is probably 20 at this point, you have quite a bit of slots to make use of now especially with arcane recovery, and you’ve gained your last wizard cantrip. 
  It may be easier to understand power surges scaling with numerical examples. At level 6 when you gain the feature, you probably have 18 intelligence. This means you could store up to 4 surges, but at this level you will only be dealing 3 damage a surge use. Not worth it to spend a 3rd level slot to dispel your own cantrips/rituals for 9 total damage when fireball is probably available to you. At level 10, you probably have 20 intelligence. This means you would be expending a 3rd level slot to deal 20 total damage in increments of 5. The value isnt immediately apparent since this is still less damage than the spell slot used to cast a  spell, but you can apply this damage on top of your other spells cast. This means with a little preparation you can basically split your spell slot into damage boosts for future spells cast. At level 12 your spending that same 3rd level slot for 24 damage total in increments of 6.
  This scaling continues, and can be thought of splitting up your 3rd level slot to upcast higher level spells, potentially increasing the damage of spells that don’t benefit from upcasting anyways. 
  6th level, 18 intelligence, 3 damage a surge, 9 total damage. 
  8th level, 20 intelligence, 4 damage a surge, 16 total damage. 
  10th level, 20 intelligence, 5 damage a surge, 20 total damage. 
  12th level, 20 intelligence, 6 damage a surge, 24 total damage. 
  14th level, 20 intelligence, 7 damage a surge, 28 total damage. 
  16th level, 20 intelligence, 8 damage a surge, 32 total damage. 
  18th level, 20 intelligence, 9 damage a surge, 36 total damage. 
  20th level, 20 intelligence, 10 damage a surge, 40 total damage. 

If you want to use up your 1 power surge you get before you dispel effects to gain surges you can choose to do so, but you will be going into battle with less damage potential.
  Using the chart on spell damage in the DMG pg 284, we can see that the damage of power surge starts off at roughly cantrip power and eventually scales to slightly less than a single target 5th level spell.
  if at any time in your campaign you receive a boon or item that increases your intelligence modifier, there will be an increase in surges available per dispel. 

  The following is an example of these features working with the well known spell wall of fire, which oddly enough takes up half of page 60 in Xanathars. Before battle the war wizard ritually casts comprehend languages and detect magic on themselves. While Concentrating the war wizard casts prestidigitation on the surface of their hand to make a symbol of mystra appear. Then casts bladeward on themselves which has a duration of one round, but ends specifically at the end of their next turn. Casts dispel magic on themselves, ending the 4 different spell effects without failure as they are all less than 4th level spells. The war wizard now has 5 power surges at their disposal. 
  The encounter begins, the war wizard rolls initiative well and gets to act first. On their turn, the war wizard casts wall of fire, which has a dexterity saving throw for 5d8 damage when it appears. The war wizard picks an opponent among the group and spends a power surge to deal more damage. If the war wizards party is is built in a way to facilitate forced movement then the creatures will take 5d8 damage with no save when they get thrown through the wall of fire again. Every time this happens a surge can be spent to increase that damage. With teamwork the party can cause increased damage against a single target by making use of the wall spell on each turn to funneling surges against that creature.

+2 to all saving throws and your AC while Concentrating is amazing, as you should be concentrating all the time. This not only makes you more tanky, but reduces the likelihood hood you will need your arcane deflection feature which keeps your spellcasting unrestricted. There are a few decent concentration cantrips available from feats or multiclassing to ensure this feature is up at all times. Guidance and resistance are amazing choices. A somewhat obscure way to make use of this ability in combat is to make use of the ready action when casting. If your worried about an enemy mage attempting to counterspell you, you can go behind cover, ready the spell out sight which casts the spell and causes you to concentrate. Then move back out and use your reaction to unleash the spell. Since the spell has already been cast behind cover, it can’t be counterspelled. You may be able to do this with distance too, since counterspell has a range of 60ft. You move out of range, ready spell, walk back in, reaction release the spell. This does use your very important reaction, so it’s not to be used in every scenario.

War wizard capstone feature. Seems lackluster, but it’s guaranteed force damage to up to 3 creatures you can see within 60ft. The damage is half your wizard level just like power surge. You get to generate and apply damage equal to 3 power surges every time you use arcane deflection. If you failed a saving throw, you were probably going to make use of arcane deflection if available anyways, so this is pure bonus  damage that costs no resources, bypasses most resistances, and doesn’t rely on a save or attack roll. It’s almost like a reaction based magic missile. The damage is comparable to a 3rd level magic missile split between 3 creatures, for using a feature you were already using all the time.

The features of the war wizard, much like the features of other wizard subclasses, make some spells more appealing than others. A “properly” kitted out war wizard is going to need to prioritize spells Based on certain criteria. 
- spells with with lasting effects.
- spells that give temporary new actions, since these effects aren’t actually casting a spell, the stay effective when heavy use of arcane deflection shuts down casting. 
- spells that require concentration, especially when durable magic feature comes online. 
- spells like counterspell and dispel magic which subclass features are based on. 

Cantrips

•bladeward-usually considered a “bad” spell, but the war wizard can use it in several scenarios that other wizards won’t be able to. 1st it can be used as the last of stacked spells that a higher level war wizard can dispel to gain power surges. This is due to the spell being non concentration and ending at the end of your next turn, which makes it last just long enough to be dispel-able. The second  scenario is when you use your arcane deflection to keep concentrating on the greater invisibility spell. Your spellcasting will be limited to cantrips, and most foes will already be attacking you at disadvantage. If you feel like you need more defense then you can cast blade ward to reduce physical damage on top of being attacked at disadvantage.

•create bonfire-a concentration cantrip. Not as useful if you choose to multiclass for another cantrip that uses concentration. gives at will concentration which can mean durable magic is almost always on or in effect. It’s range means that you can ignite flammable materials at 60ft range at will too. While not nearly as effective as leveled spells, it also presents a low/early level option for your group to take advantage of forced movement damages.

•Dancing lights-another at will concentration spell to use durable magic. this one generates light for you and your party members that might lack dark vision.

•firebolt-your highest damage cantrip utilizing attack rolls ciming in at 1d10. This cantrip has a 120ft range for its attack. This cantrip can target both creatures and objects. You may find yourself making use of this quite a bit depending on your spell selections and use of arcane deflection.

•Frostbite- a 1d6 constitution based save spell for 0 damage. If the target fails it has disadvantage on its next attack on top of taking damage. Not very reliable, but can greatly reduce the damage potential of creatures that are designed to do the majority of their damage with a single attack.

•gust- usually considered a weak spell, but with the war wizards features this spell can find niche uses. If arcane deflection has been used to maintain a spell effect your concentrating on that causes an AOE, gust can be used to potentially push a medium or smaller creature back into that effect. It can also be used as a way to move an ally out of an enemies reach without provoking an opportunity attack.

•light- can be used to provide light without concentration. If your war wizard is deciding to gather spells that target objects instead of creatures to gain power surges via dispelling, this is a good pick.

•lightning lure-can be used to pull a target within 15ft if you to you if that target fails a strength save. That target would also take scaling 1d8 lightning damage if the target is pulled to within 5ft of you. Can be used to pull creatures short distances into on going effects if you maneuver around appropriately. Cloud of daggers can be used somewhat effectively with this spell since it takes up such a small area.

•magehand-an amazing utility spell. You may want to pick this if you’re planning on taking the telekinetic feat to boost its range while providing a reliable bonus action to further increase your forced movement potential.

•message- another utility spell that can help with communication and secrecy. This spell lasts for 1 round, but that’s not quite long enough for you to cast yourself and dispel for power surges. Have an ally take it to cast on you if they are willing to work with you to generate surges, and also actually want the cantrip themselves.

•mind sliver- an amazing cantrip that can really set up a war wizard. This cantrip penalizes a targets next saving throw, does scaling 1d6 damage, and also targets an attribute that is typically low. This cantrip also doesn’t limit you from targeting yourself, lasts one round, and also lasts until your next turn(like blade ward). You can potentially target yourself if your willing to take a bit of damage to gain surges, but I’d rather use bladeward.

•mold earth-can be used in a variety of ways. Create defensive teenaged quickly, dig or otherwise easily move portions of lose dirt and stone. Can also target certain types of objects with non concentration effects that are dispel-able.

•prestidigitation-a very versatile spell that has a lot of role play and utility potential. The ability to Mark/color/or make a symbol appear on an object or “surface” means it can also target the surface of a creature. A nice dispel option since that lasts for up to an hour non concentration.

•ray of frost-a low damage cantrip that can reduce a creatures speed by 10ft. Could be useless, or could enable the party to stay entirely safe if a targets speed is low enough.

•shocking grasp-can be used depending on spell choice set up for an action attack accompanied by a weapon used bonus action, such as storm sphere. Can be used to take a creatures reaction away if the attack lands, could be a great option vs other casters. If you hit another caster that has shield and counterspell, they have to choose between counterspelling as you cast the spell and letting the spell go off for a potential shield cast to potentially make the attack miss. it’s a great way resourceless way to try and take away reactions. Also, if used with stormsphere, it can be used to potentially take away the reaction for your targets opportunity attack so you can move away and bonus action attack with storm sphere without disadvantage and possibly with advantage.

•Swordburst-a low damage AOE that targets all creatures within 5ft of you. Dex save for 1d6 force damage, does t require sight, and allies may be subjected to friendly fire.

•thunderclap-a loud swordburst that targets constitution instead of dexterity. Also deals thunder damage.

•toll the dead-potentially your highest damage single target cantrip. Targets a wisdom save, 60ft range, dealing necrotic damage. Damage die scales from 1d8 to 1d12 if the target is missing hitpoints.

•truestrike- concentration, so durable magic can be used with this cantrip. That being said, this cantrip is probably still trash. Damage wise your probably better off casting a damage dealing cantrip than using this spell, even if you’re out of slots or limited by arcane deflection. The wizard spell list doesn’t seem to have a big single target attack roll spell that would make this cantrip useful, though planeshift could be somewhat bolstered by this cantrip.

Put your spoiler here.

If multiclassing is available I highly recommend a one level dip in either artificer or cleric. Both continue your full spellcaster slot progression, give armor and shield proficiency, give additional cantrips for utility or forced movement(thornwhip), and provide spells that the wizard may not have access to. Artificer frees up low level wizard preps with slight overlap but also makes use of the same primary stat. It gives the option to prepare and cast the cure wounds, faerie fire, and sanctuary spells while using intelligence. Magical tinkering can go quite far for imaginative folks.

Cleric preps less spells because of wisdom based casting. This is made up for by an additional cantrip, domain spells, and other subclass feature options available at level 1 such as heavy armor if wanted. Quite a few low level cleric spells are effective without reliance on wisdom. Stand outs include spells like Bless and Shield of Faith which work directly with your durable magic feature. Create or destroy water has niche uses along with detect evil and good, detect poison and disease, protection from good and evil, and purity food and drink.
  Order domain is my favorite war wizard as voice of authority feels very tactical when giving allies reaction attacks when they are targeted by your Magic’s(even if it’s not a buff and they get caught in a fireball...). A  turn where you spend your action to cast a cantrip and your bonus action to healing word an ally(for 2-4 hitpoints) such as a rogue or paladin to allow them to make a devastating attack may be a fine use of a 1st level slot.
  Arcana domain can be wonderful since it gives all those extra cantrips for utility and will be useful for power surge generation without sacrificing offensive cantrips. it’s domain spells are effective and don’t rely on wisdom at all which is rare for cleric domain spells.
  Can see twilight and peace domain being very impactful with release of tashas.

As always, a 2 level dip for arcane deflection is great for a reliable AC and save boost. Especially for builds that have little to do with leveled casting while in combat.

If multiclassing is not available I highly recommend a racial option that has armor proficiency, an armor bonus, some sort of natural armor feature, or temporary hitpoints.

Dipping
2 levels in wizard to gain the arcane deflection feature is quite powerful for a multitude of classes. The 13 intelligence can be difficult to overcome for most builds multiclass builds, but the benefits gained can be worked around to either minimize the low intelligence DCs and spell preps or synergize with 1/3rd caster subclasses enhancing versatility.

2 levels of wizard and the choice of war wizard tradition gives the following as benefits.
-3 1st level spell slots, or 2 full caster levels of progression.
-1 spell slot restored once a day during a short rest.
-access to 3 wizard cantrips of for utility or damage supplement. 
-access to 8 different 1st level spells. 
-access to ritual casting directly from your spellbook if spell preparation is limited. 
-your intelligence modifier to your initiative. 
-access to arcane deflection as a reaction, which can heavily boost known save failure, and whose spellcasting limitation afterward can be very easily circumvented on class build featuring extra attack.