Not actually true, rshamans need to riptide and ES for max healing, druids have to stack blooms, hpallies have beacon, glyph of flash heal and not sure if anything else.
Just making sure we don't get too biased here.
What do resto shamans need riptide for? On my shammy the only function riptide serves as is a decreased casting time for GHW/HW and crit for healing surge. Let's be honest here as well, shaman have zero problems with throughput. Having riptide/earth shield on their targets is just icing on the cake. I guess you could argue unleashed elements, but that isn't nearly as annoying as stacking grace.
Lets not forget riptide is an AMAZING heal. It is superior to renew in every way. If grace was an amazing HOT like riptide, stacking grace would be acceptable.
Druids do have to stack lifebloom, however they fixed it by making it transferable with a glyph. Lifebloom also instantly begins healing. The grace buff doesn't do anything except increase heals. MAYBE if grace stacks were transfered to other party members it would be ok, but having to build stacks on all of your teammates is a problem.
Lifebloom never falls off like grace does. The druid just has to keep it rolling and can transfer it immediately.
Holy paladins build up holy power, but that isn't restricted to any specific person. It is tied to the paladin and he can spend it wherever. Grace stacks on the TARGET. MAYBE if grace stacked on the priest instead it would be fine.
I can't comment on Grace as I am biased from tradition.
It is a tradition that needs to be removed. Buff priest heals and make shield undispellable. We are the least mobile of the healers and juggling grace is annoying.
This is the way it's supposed to be, we were built mechanically well in that design
If that is the case then almost every single other class was poorly designed. I'd rather be brokenly overpowered like the rest of the classes than a gimp fish in pond full of sharks.