I don't think anyone can argue that the "order" of DPS/mitigation is incorrect. Warriors should do the most damage in dps and tank stances, but mitigate a tiny bit less. Dark Knights should be "mid tier", and stronger on magical damage. Paladins should be lowest dps, highest physical, slightly behind DRK on magical, with the DPS made up for via slightly more utility. That's how it is, that's how the classes have been sold to us, and that's how it should be.
Making comparisons that because, say, Sentinel is 10% better than Shadow Wall during its 10 second uptime means that Dark Knights need 5% more damage in x situation is kind of spurious and highly subjective. Overall balance matters and it's due to the complete package of how much weight a raid group places on the various strengths and weaknesses.
I think most peoples' issue with the current balance is:
1 - right now DPS is exponentially more important than overall tank mitigation for successful encounters
2 - the difference in DPS levels in "average" practical raid situations is really rather big
3 - the actual difference in mitigation levels is comparatively minor compared to the DPS differences.
This creates a situation where all 3 tanks are in the right place in terms of the order of their power levels, but the balance is swayed heavily in favor of Warrior. Noone wants paladins doing more or even equal dps to a Warrior. Everyone would be happy with paladin being behind dark knight too.
The class just desperately needs some quality of life buffs (read : basically threat, some "clunk" removed) that lets it push out its optimal DPS levels much more frequently and thus close the huge gap between itself and the other tanks in practical (not dummy/pure OT) situations.
