The only way for healers to not need to dps is for them to change how the encounter goes a.k.a non-scripted. In a scripted environment, there will always be room for healer dps because everything has a set pattern so oGCDs can be planned out. Raising the raidwide damage will only serve to cause more wipes and lead to more frustration in parties. Healers were not designed and optimally (especially in raids) played with GCD healing.

What needs to happen is either they make healer kits interesting so it's not just "one-button spam." Be it a more diverse dps rotation or more support.

While I'm not fond of enrage timers, so much of the fights are just dps checks after learning mechanics.