Honestly, solid idea. 4 player casual content isn't supposed to be hard. And I agree that healers are punished harder for being worse. (Or, we're all punished harder for the healer's mistakes.)

Deep Dungeons allow Phoenix Down and that feels good. They're unique items so you're only allowed to bring one. In that way it kind of functions like the limited Criterion res.

This is how they can remove SMN's res in 8.0 and not upset everyone.