Dark Knight is not balanced. To be clear, this is not about meta, this is about offering something of value to a raid team that is unique. You have responded to our feedback that it is your feeling tanks are in good shape, the response is greatly appreciated after months of silence and I ask that you expand on this and continue the conversation.
It is my proposition that Dark Knight is not balanced with respect to warrior and paladin on three fronts: DPS, Mitigation, Utility.
Damage: In both the main tank role and off tank role, dark knight appears to have lower damage output in practice and theory when compared to paladin and warrior. The difference appears to be smaller when in the main tank role, but appears to be larger in the off tank role. On its own the difference appears to be smaller, but noticeable.
Utility: Dark Knight brings a single unique utility, The Blackest Night. This utility can be used frequently, and nearly breaks even with its own cost. The issue with The Blackest Night is that it comes with an inherent risk of not breaking, and this is not made up for with any reward for executing the move properly. As a utility, if it can be executed on cooldown it will mitigate about as much damage as Divine Veil or Shake it off, but has an accumulated damage loss for the dark knight.
These three skills are not comparable, because two of the three moves are raid wide mitigation. Two tanks having raid wide mitigation is a reason against bringing a dark knight which does not offer any type of equivalent for dealing with raid wide damage. Especially in raids with lots of raid wide damage like V4S.
The main gain of The Blackest Night is to give healers back a GCD. However, given the semi unpredictable nature of when it will go up you need to be in communication with your healers as to when it will be used, which is not always the case in pug groups and so this ends up getting treated like parry -- heal like it isn’t there. This removes value from the skill.
Mitigation: Dark Knight has the lowest uptime on mitigation of any tank in the game right now. In In tank stance, Paladin has 3 defensive cooldowns and passive blocking; Warrior has 4 defensive cooldowns, a parry bonus, and lifesteal built into its rotation; Dark Knight has 3 defensive cooldowns and lifesteal. But our mitigation is universally weaker than the equivalents on Warrior and Paladin without investing more of our lower dps into defense.
In tank stance, at max gear level it appears that The Blackest Night no longer breaks to auto attacks in many raids, which negates its short cooldown advantage because it cannot be used frequently, meaning it has to be saved for cleaves or busters where it doesn’t always mitigate enough to keep us alive, meaning it must be paired with another mitigation anyway. Paladin's shelltron is a huge amount of mitigation at max gear level, 26% of an attack blocked, and on tank busters in savage this move outperforms the blackest night by a nice margin and comes as no dps cost to the paladin. Assuming we are in tank stance comparing this to inner beast is a mixed bag, sometimes the blackest night mitigates more, sometimes Inner Beast mitigates more, but Inner beast in tank stance is definitely a boost to warrior's dps and gives more lifesteal. Out of tank stance I would compare The Blackest Night to Thrill of battle, except that Thrill has 4 times the duration and synergy with damaging moves for warrior.
Shadow wall has the mitigation of vengeance, but is weaker in terms of duration and cooldown. The higher uptime means that vengeance will mitigate more than 125% more damage than what shadow wall does over the duration of the encounter while also granting a counter attack for the warrior, I’m not sure what this is meant to balance out with in the dark knight kit. Maybe this is meant to balance out with Warrior’s stance, but this makes things worse if we choose to tank without our tank stance. The situation is not as bad with Sentinel, but we still mitigate less here 10% is not huge, but it is worth noting.
Raw intuition has a higher up time and mitigates more damage than dark mind, and Bulwark has half the uptime of dark mind but mitigates about twice as much and ignores the type of damage.
All of the above assumes we use tank stance.
If we assume a low uptime on tank stance, as many players drop their tank stance for a significant portion of the fight, we have the same issues, but it is made worse as no tank has a defensive buff when out of tank stance. Warrior loses one of its mitigations in dropping its stance and a parry bonus, but retains its combo life steal and its higher uptime on mitigation, Dark Knight does not lose mitigation but does lose an avenue for dealing with incoming damage in its lifesteal being grit locked, The Blackest Night will break on autos (with great care in our timing to catch two autoattacks) but no longer offers a reward since without grit it is a nearly break even (risk without reward). Paladin does not lose much in tanking in sword oath, it even fills their gauge faster than in shield oath.
Nothing on its own is so massive as to make Dark Knight not viable, but all three of these together make Dark Knight undesirable to run in raids.
Given the above, I don’t see how dark knight is not in need of adjustments and can be claimed to be balanced with warrior and paladin. Can you please elaborate on how you think Dark Knight is balanced?