In that case the question is, has Pacifist Healer been unbalancing in practice as is? We've got several examples with DM's and players to ask. So far River has been the main example, my character Pok has been traveling with him, and I haven't seen any encounters reduced to triviality due to his presence.
That may just be due to r1's ability as DM though...
I've seen it unbalanced in actual play. This encounter went from challenging to a trivial mopup with the use of a single power:
Knoepf 26/40
Hasifar 0/41 prone, bloodied and unconscious
Artemus -2/39 prone, bloodied and unconscious
Boruuk 20/51 prone, bloodied
Tirial 11/45 bloodied
http://www.enworld.org/forum/5062389-post121.html
Knoepf 26/40
Hasifar 26/41 prone
Artemus 25/39 prone
Boruuk 48/51 prone
Tirial 38/45
The party was in desperate shape. But with a single prayer, the Pacifist Healer Knoepf healed 106 hit points or 10 healing surges worth of healing. In 3E terms, that's the equivalent of a Mass Cure Serious Wounds for a 4th level PC. In 4E terms, that's stronger than casting 4 6th level Cure Serious Wounds spells simultaneously, or stronger than casting a 22nd level Mass Cure Serious Wounds.
You don't consider that giving 4th level PCs the ability to cast 22nd level prayers as broken?
Granted, not all of this healing comes from Pacifist Healer. Only 32 points or 30% came from Pacifist Healer, the rest came from Healer's Mercy and the plethora of healing bonus items and feats that healing type Clerics accumulate.
River has two powers that can do this. His group is never really challenged unless River goes unconsious or is stunned.