It is only bad when the healer doesn't remember when the plumes are coming and try to cast Cure at the wrong time. Plus, good PLD tanks will use Sentinel or Flash to migrate/dodge damage and it just isn't as bad as you think. Even further most of us just spam Medica I/II (other than the first phase when tank has not enough hate), barely any skills needed.
The only real nightmare is when the tank doesn't know the Rock Bomb's "sweet spot" and try to dodge in the normal way like everyone does, jeopardizing the entire group since some of Titan's normal attacks are also AoE I believe.
I have yet to win with a WAR tank, tho.
