Sorrow Knight?

Quote from Caerwyn_Glyndwr >>

Quote from Iza_Fox >>

Quote from MaedraDawnkeeper >>

Regardless, tying it to Tactical Shift OBJECTIVELY makes the feature worthless in practice.

Let Martials do cool things for no cost because they have less total & less varied resources than casters. Please.

I agree.. it went from already BARELY worth playing and semi-garbage.. to... purely garbage. Noted. They REALLY need to let Martials be able to do cool stuff that at least lets the ATTEMPT to keep with Casters. Cause currently even the best Martials are you geussed it... Casters. Some of them are EVEN FULL CASTERS.. and not Half or Quarter Casters. Shit they still can't even get Arcane Archer right.. that poor thing is still worse than just playing a Ranged Battle Master with Magic Initiate..

The Teleport thing was really the only thing it had going for it compared to normal Battle Master.. or most of the other Subclasses. Now its either Waste your Self Sustain to Teleport.. or Don't teleport until after you take damage.... weee....

Desparing Strikes = Only better than Battle Master cause its Psychic Damage.
Darkvision = Usually always neat, this even extends your sight if you already have it.
Empathetic Inquiry = Useless
Dreaded Appearance = You get it just before it becomes useless cause all the things with Resistance or Immunity to Frightened that start becoming more and more common around that level.
Unsettled Strikes = Okay at best, would be better if the Exhaustion one wasn't capped at 2 Levels
Grim Constitution = Would be good.. but it's About.. 7-10 levels too late to be super useful, especially if you are in any kind of Ravenloft or Dread Planes Campaign.
Grieving Mantle = COULD be cool.. but requires you to Use your Action Surge first. With Shade Form being its only redeeming quality. Unwavering Resolve, should be the level 10, level 15 at the ABSOLUTE latest. Considering basically anything else that gets a similar effect had it online around levels 7-10.

 
A lot of this analysis is questionable at best, and make me highly suspect you do not actually play games at tier 4.

- Calling Empathetic Inquiry “useless” is hardly a fair critique of the ability.  That is something fighters already struggle with, so giving them a fun, unique ability that does not just copy existing parallels is solid design.  Moreover, there are plenty of ways that this would be great for roleplay, both with other party members or allies.

Firmly an ability in the “only useless if you can’t figure out how to use it” category, which is the fault of the player, not the ability. 

- Dreaded Appearance.  For starters, frightened is a condition, not damage, so you cannot have “resistance to frightened” as you suggest in your analysis.

It also is bad analysis. While immunity to frightened does proliferate at higher levels, any halfway competent DM is going to ensure they are choosing monsters that are not immune to party abilities all the time.  Moreover, there still exist plenty of monsters DMs are likely to use, especially as secondary monsters, that are able to be frightened.

But let us pretend you have a point and assume arguendo the frightened component is worthless.  You would still be wrong in your analysis of this ability.  Taking an already useful ability and making it better is nothing to scoff at - teleportation is a huge boon and extra psychic damage for something you’re going to do anyway is a nice little extra.

Grim Constitution - Psychic and Necrotic damage becomes pretty common at high levels, both from monster abilities and nasty things like Finger of Death.  Reduction of hitpoint maximum is not as relevant, but something that, frankly, both Wizards and DMs should employ more often, particularly at the levels this ability kicks in.

Grieving Mantle - Another analysis that suggests you do not understand high level play.  Properly equipped Fighters at high levels are the energizer bunny of classes, able to churn out consistent damage more than anything else.  Their one problem is that the one super cool thing they can do in combat - action surge - is often tossed out early (to put a large dent in the monster and reduce the risk you kill it halfway through your extra attacks, feeling like they’re wasted).  After that, less cool to play.

This is very clever design, working well with what  fighters are already going to do, while leaving behind a neat, extremely powerful effect (monsters at that level can easily do absurd amounts of damage, so negating a single hit is a substantial benefit).

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All told, this is an extremely cleverly designed subclass.  The folks who made it clearly understood the fighter playstyle and created abilities that work well with that playstyle, while also making the abilities feel flavorfully unique.  

 Okay lets unpack this. I have indeed seen lots of Tier 3 and Tier 4 play. 

Empathic Inquiry= Cool you get to learn a creatures emotional state, good for RP. BAD because they immediately know you did it, AND you get 0 context on WHY their emotional state is as such. It COULD be a good and cool RP ability. But in its current state, I guarantee you with the lack of context and the fact that the target IMMEDIATELY knows what you did. Is only EVER gonna make the situation worse. Nobody likes having their minds read or influenced. 

Dreaded Appearance= Yes. Cool it does Psychic Damage IF they fail a WIS save. The second most common Save among Spells, and 9 times in 10 any Tier past Tier 2, Odds are. That Save is being Succeeded. A Creature ABSOLUTELY CAN have Resistance to Conditions. Even Several player species do. Its called "You are resistant against Condition XYZ, so you have Advantage on Saves Against that Condition". Which Guess what. Advantage against Frightened, Charmed and Poisoned Conditions are the three most common Conditions to amongst Monsters. And Yes Higher Tiers of play Things being Immune to Frightened becomes significantly more prevalent. INCLUDING in Modules, which see a ton of usage and play. Sure in a Homebrew game, you might see it less. But I can tell you that over at least 2 Dozen different Groups/Tables both Module and Homebrew that I have played in since 5e came out. The only time I have ever seen Frightened really end up working is Tier 1, sometimes Tier 2. and or Trash Mobs from those Tiers that by Tiers 3 and 4, you are probably 1 or 2 tapping with basic attacks. Yes it does do Psychic Damage, but its a SINGULAR Die of it, on the 2nd Most Common Save Stat. With it ALSO being tied to Second Wind/Tactical Shift.

Grim Constitution= Yes the Resistances are good, and become more prevalent. That I need to clarify is not my problem with the ability, though I do think those should come earlier. ESPECIALLY since the Campaigns that tend to get the MOST use out of those Damage Types. End Early-Mid Tier 3, such as Ravenloft. The Main concern is the Immune to Hit Point Max being reduced. Most things that are going to do that to a player are in Tiers 2-3. Or Tier 1 if you are ya know.. in Ravenloft... I'm looking at you Death House. Grim Constitution IS a Good Ability, it just comes WAY too late. Yes WotC and DMs should implement things this would work against more often, but until they do at the level you get it. It's just not that great.

Grieving Mantle= The MAIN problem here IS the fact that it is Tied to Action Surge. For the very reason you mentioned, if it wasn't tied to Action Surge and was just a thing you could activate once per Rest on its own, it would be more useful. Unwavering Resolve is STILL way to late game wise to become immune to Charmed and Frightened. Especially when other Classes get same or similar effects as Early as Tier 2. And Creature you are going against already had Resistance(ADVANTAGE) or Immunity against those effects since you were in Tier 2.

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With that said, yeah its cool and it has flavor. It could be cool to play in Tiers 1 and 2. But all experience I have had with 5e and 5.5e past Tier 2, this isn't gonna feel as great. When you are still being effected by things that most or your party are probably already shaking off or ignoring, and your cool creepy scary appearance is gonna deal a whopping 1- 6 damage, cause things Succeeded their Saves. Not to mention anyone you try to Read the Emotions of is probably gonna draw a Knife or Worse on you the moment you did it, cause people hate having their minds read or manipulated in Any way.

The very first thing I thought of with Dreaded Appearance is to teleport into or right before a group of enemies and Cleave with a Greataxe or Halberd. By level 7, that would be quite a lot of individual attacks with Action Surge (which also means a lot of possible critical hits) and if most are Frightened, they aren't really going to be able to hit you back. For an ability that you can only use once per rest, I think there is potential to wipe out or heavily damage a group of enemies in just one turn.

You could also do other combinations like Push with Tactical Master and Polearm Master to hit them again when they reenter your Reach. 

I don't know, I think the Sorrow Knight is pretty rad. 

Cleave is 1 extra creature 1 per turn. But yeah, could be cool in that situation. At Level 7 if you Action Surged you could maybe hit 5 dudes. But you could also just do that if you were the right kind of Goliath, or any of the Elves that get their Psuedo-Misty Step effects. All of which could also do it WITHOUT wasting a Second Wind

Quote from Iza_Fox >>

Cleave is 1 extra creature 1 per turn. But yeah, could be cool in that situation. At Level 7 if you Action Surged you could maybe hit 5 dudes. But you could also just do that if you were the right kind of Goliath, or any of the Elves that get their Psuedo-Misty Step effects. All of which could also do it WITHOUT wasting a Second Wind

 Yeah, but now I don't have to be the right kind of Goliath or Elf, and the Misty Step doesn't add Frightened and Psychic Damage. You can just say you really want to hate this subclass and will refuse to be swayed. That's totally fine. 

Quote from Erik_Soong >>

Quote from Iza_Fox >>

Cleave is 1 extra creature 1 per turn. But yeah, could be cool in that situation. At Level 7 if you Action Surged you could maybe hit 5 dudes. But you could also just do that if you were the right kind of Goliath, or any of the Elves that get their Psuedo-Misty Step effects. All of which could also do it WITHOUT wasting a Second Wind

 Yeah, but now I don't have to be the right kind of Goliath or Elf, and the Misty Step doesn't add Frightened and Psychic Damage. You can just say you really want to hate this subclass and will refuse to be swayed. That's totally fine. 

Fair on the Frightened/Psychic rider effects, and it being something you can do without being a Goliath or one of the Elves. Though Eladrin get similar effects that could.

I also do not hate the subclass, I think it could be cool to play. It just definitely has some problems.