I'm putting my TLDR; at the beginning:
TLDR; Living Dead takes more resources to handle than any other tank. This is not balanced out by an especially strong mitigation kit. Nor is this justified in terms of drk’s personal damage output. While the skill isn't to the point of unusable, it could use an adjustment to bring it inline with the usability of the other invulns.
I see your point that any healer can cleanse living dead, and I agree with it. In perfectly planned environments where everything goes according to plan you can achieve this. But let's also recognize that not everything goes to plan, and sometimes in the heat of the moment we don’t realize the consequences of how we react will domino down the line. Plans are great until things don’t go according to plan, that is half the issue with this skill.
Here is the other half:
5 oGCD’s and 1 GCD to fully cleanse walking dead. Here are some other ways that can get handled:
The same situation but not a dark knight:
Hallowed - just top me off depending on my HP and nothing gets wasted.
Superbolide - Yes I’m at one hp, use one oGCD and we can tank swap at the end and I’ll regen my own hp. This works really well when the invuln goes into something like a trio, or other ultimate mechanics where you aren’t taking damage and can just get a regen from a healer for the down time.
Holmgang - about the same as superbolide. Put one oGCD on me tank swap and wait till I have equilibrium or a burst window with nascent flash. I did a pf with a warrior who holmganged the double slap, then without being healed at all nascent flashed their next IR window to full hp.
Our defensive kit must be the answer. One way around this obvious weakness is to simply not take damage.
What is below looks way better as the table I have in docs sorry!
DRK
Dark Mind
20% Magic Mitigation
TBN
42.5k shield on self
Empty
WAR
Thrill of Battle
20% HP +20% HP restore
20% Bonus to incoming healing
Nascent Flash/Raw
Either a heal or 20% mitigation
Equilibrium
32k heal
GNB
Camo
10% mitigation
50% increased parry chance
Heart of Stone
15% mitigation
Aurora
5.4k Regen
~32.6k heal
PLD
Empty
Sheltron
20% mitigation
Empty
Lets run some hypotheticals: AOE is coming up and I want to reduce the amount of healing I need. Lets say the aoe hits in the average range of 40k hp and an auto hits for 18k.
DRK - TBN Dark Mind! Ok dark mind takes 8k of that aoe, TBN takes the 32 and 10k of auto attack that does 18k. We mitigated 50.5k hp!
GNB - Camo Heart of stone + Aurora! Ok Camo soaks 10% of damage for the next 20 seconds, that covers about 6 autos and the aoe. 14.8k mitigated. Heart covers 15% of 2 autos and the aoe (but 90% since camo was up too). Thats 10.2k mitigated. + Aurora + 32k HP. Total HP saved: 57k (25k Mitigated)
Take out any 1 of the skills except Aurora and you end up with about a 10 to 12k difference. If 5 oGCDs and a GCD planned into living dead is nothing, then a 10k difference in damage taken in autos during an aoe is a rounding error. Lets say we will only use Aurora or Equilibrium on busters. We are still only talking about 25k difference in damage taken. This isn’t alot when raid wide healing is going out which will heal more than this back since everyone else takes way more from raid wide aoes (estimate about 50 to 60k).
Lets look at tank busters. 60 to 70% of the tank busters the past two tiers have been physical. Crippling blow is one example of this, many tanks use dark mind on this and turns out it mitigated nothing. Given that we are struck by lightning you would think magical but its not, test for yourself. Every buster in e6s is physical, double slap in e8s is physical.
What this means: Dark mind isn’t getting the mileage it used to when so many busters were magical and dark mind could be up for all of them (e2s as an example of how abusable this skill could be).
DRK - TBN + mitigation every tank has in addition! Dark Knight takes 42.5k less damage because of TBN.
GNB - heart of stone + what any other tank would use! So the extra 15% mitigation depends on how much damage we would take for how much it would mitigate. For crippling blow we could take as much as 65k and we would mitigate about 10k which is a 32k difference which is the damage healed by aurora or an unbuffed equilibrium.
By the ways these are set up you can easily translate the same numbers from GNB to WAR and see warrior is in even better shape than GNB. And you can see by not over mitigating GNB and WAR can both cover all the situations because they have the cooldowns for it. DRK just has one button where everyone else has 2 or 3.
The exception here is Paladin. Paladin is probably at a disadvantage in mitigating except when it comes to the very powerful hallowed ground.
Handling Invuln ability: PLD > GNB ~ WAR > DRK
Mitigation: DRK ~ WAR ~ GNB > PLD
Dps: GNB > PLD > DRK ~ WAR
Tilda here meaning approximately equal but order reflects my preferences here.
TLDR; Living Dead takes more resources to handle than any other tank. This is not balanced out by an especially strong mitigation kit. Nor is this justified in terms of drk’s personal damage output. While the skill isn't to the point of unusable, it could use an adjustment.