In what way does paladin have "more mitigation"? A shield is a very minimal factor.On top of the fact mitigating more isnt exactly useful when less mitigation still leaves you in a safe spot.
Every tank has a cooldown for a tank buster, they will survive with that cooldown and be healed.
Everytank has a minimal cooldown for AAs.(foresight,bulwark etc).


I dont think its a fair trade off of less dmg for More mitigation when every tank will take around the same damage and be fine.


Rather, paladin has the EASIER mitigation. (i hvnt leveled drk so excluding it) Plds are very simple, press a button, less dmg. Compared to wars who have one of there major cooldowns tied to unchained while its also part of the GCD which requires attention and knowing the fights to be effective.


For a tl;dr - pld and war mitigate roughly the same, its just mch easier and thus more noticeable on pld, but war also gets high dmg