I watched a 30k hp Ret Pally take on a Feral Druid tank with 50k hp. He killed the Druid since he had a heal that could heal him back to almost full, basically the ability to Lay on Hands over and over at no cost to him in mana nor debuff. I find that a bit much.
But, I think the biggest annoyance are tanks, who no longer care if their group, including their healer, is with them, because they can now not only faceroll with damage, but heal it all back again, at no cost to them.
TL;DR - I see the utility of the spell, shouldn't it be dumbed down some for Ret and Prot in some way?