Kosmos, You don't have everyone stun because if everyone stuns too much, the stuns won't work. Up to Titan, you will only be on stun duty for Ifrit and Chimera so you're MT or OT majority of the time in end game.

CK11, only stun eruptions and have your team dodge the plumes. Even though stuns become resisted over time, they also have a cool down where the resist goes away.