Hey hey, just a post on Reddit. I thought I would transfer it here. Feel free to add feedback or add your own suggestions.
Reprisal - When blood weapon is active, it can proc on a critical strike. Bam, problem fixed.
Dark Dance + Dark Arts - Whenever you parry an attack you restore 5-10% of your TP.
Soul Eater + Dark Arts + No Grit - Restores TP instead of HP.
If they just added those three features, I would have no issues for Dark knight. As for Delirium, I think it should not stack with monk, but add an additional effect. I'm thinking 5% more magic damage taken would be better, it can be applied with dragon kick, but doesn't lower int more than 10%. This would increase Drk dps, remove the requirement of having a Mnk for DK to progress and make it a priority on rotation instead of Soul eater taking all priority with dark arts. Also it wouldn't make bards obsolete. If a dark could increase magic damage 10%, then machinist would be supreme, since the machinist biggest weakness is no foes requiem.
Regarding the EHp, I think we're fine to be honest. Do we mitigate as much as paladin? No. Do we have as much Hp as warrior? No. However we drain tons of health that needs to be considered for EHp. After we take that big 8,000 damage hit, we can souleater right after with bloodbath and restore 1500 of that. When it comes to AoE pulls we're monsters. Now that Abyssal Drain is fixed, its like a full heal every time you can afford the Dark Arts cost. Insane AoE damage for a tank, Insane AoE threat, Massive evasion combining DA + Dance with the Blind. I think when we get geared, Drk will easily be the speed run tank. Also magic damage, I'm certain more and more raid bosses are going to have magic damage tank busters. Look at the sphinx thing in the dungeon that escapes my mind right now. My dark knight takes like 1200 damage from the tank buster while my paladin takes 4,000. It happens too often for a paladin to rotate cooldowns for every single one, while the dark can keep the magic mitigation up all the time. Both the MR cooldown, the debuff and reprisal all have a lot of up time.
Also speaking of geared, once we get some of that Alexander gear I see no reason to bring a paladin. If a dark knight can main tank without dying and do more damage than a paladin while main tanking, why would you want to bring a paladin? Excess mitigation doesn't benefit the group.