Hmm. Killing Titan in heart phase... downing the nails in ifrit. Conflagration in turn 5. Silencing/ Stunning? Barding songs? Debuffs?
Silly you saying that DPS have no responsibility. Tanks once they are settled have to do less imo. I prefer tanking Ifrit then DPSing him.
Healers have the hardest job imo. But still its pretty even...