Souleater

[Freyyy]

If it doesn't increase your current HP, and it doesn't count towards Living Dead, then it probably isn't a heal. Let's get that out of the way lest we start classifying other forms of damage reduction or negation such as Hallowed Ground as "heals".

Well TBN is technically "effective healing", just like Adlo/Succor's shield component (it's even counted as healing in FFlogs). But I agree that it shouldn't be considered as such when it comes to TBN and DRK's kit as a whole. DRK still lacks self-healing in single targets outside of Grit, and if you really wanna count TBN as a self-heal, then DRK severely lacks mitigation. In both cases, DRK lacks something defensively.

[Lyth]

...

Oh, I knew exactly what he/she was getting at. The reason why some unofficial metrics treat fixed damage mitigation as "heals" is because it provides a means of comparing the healer workload. That isn't to say that healing and mitigation are equivalent. I think most tanks understand this intuitively, because TBN will not let you solo a mob indefinitely. Self-healing, however, can, as long as you can provide at least an equal amount of healing on average to the average damage received. Officially, TBN isn't treated as healing either, as activating it doesn't count towards the healing requirement on LD, while Grit Souleater does.

If you want to find an analogy between HP and mitigation, consider how Defiance works. There are two parts to it: the eHP bonus, and the %healing bonus. eHP determines your ability to survive spike damage, but does not influence your average healing requirements. %healing bonuses offset your average healing requirements, but don't influence your ability to survive spike damage. Mitigation moves which have a percentage chance to succeed, such as Anticipation or Bulwark, also usually fall under this latter category (outside of multi-hit tankbusters). In a way, you can think of the passive self-healing from Grit Souleater as being analogous to PLD's passive block, except that theirs is not stance dependent.

I chose not to entertain the tangent because it derails the discussion from the real issue at hand, which is DRK's lack of self-healing.