The idea that we need to DPS must go.

[Doragan]

I just ran into yet another example that couldn't keep all group members over 50% in a simple dungeon, so when we got double room wides on a boss, only the tank was left.

What about it? It's ok to do mistakes in a dungeon, and more importantly, it's ok to wipe there. It's a dungeon, no one cares. There's no stakes at play there.

Healers are there to heal, not try to milk a stat that's already so low and do next to nothing helpful for the group

Healer AoE DPS is ridiculously good. In levelling dungeons, there's times you can even outDPS DPS jobs. Holy can stun enemies until they hit the floor. You have so many oGCDs to get everyone to max HP.
The incoming damage in this game is ridiculously small. However, you need healer DPS whenever there's any kind of DPS check in harder content (where your kit is stretched).
Let's try to do get to p4s p2 without healer DPS. Even adds in p3s. I'm sure not passing 50% hard enrages would be "helpful" to the group.