I think that we also need to consider that if Cleric Stance was increased by a high percentage (say 20% or more), how long will it be when SE have to consider healer DPS for content? Sure the DPS that healers bring isn't game changing but having a high increase needs to have some kind of reprecussion.

OP mentioned Wisdom of the Aetherweaver from Pyros, but there were also some other actions there that could be more welcome for healers in terms of damage potential. It's either give healers more damage opportunities when it comes to fights, or increase the famage the party receives so more healing is actually required.