I'll be really frank here. I don't think the group portion of the heal is long for this world. I personally dig it and I feel smart when I see 5 people in a group all at once who need healing. It makes the spell different from other AEs.
On the other hand, it's pretty gamey. (I can only heal these five arbitrary people, why?) Priests feel like they have to ask raid leaders to set up groups with their weird AE spell in mind, which is really unlikely to happen in Raid Finder. It doesn't work at all on encounters like the shrines in Sha of Fear.
We're not going to change it for 5.2. We're probably not going to change it for 5.3. But I sense the writing on the wall here that it won't last much longer. I can imagine a future iteration where Prayer of Healing is the AE equivalent of Gheal and Circle of Healing is the AE equivalent of Flash Heal. (Yes, I know Disc doesn't have CoH - I'm in a really theoretical space here.)
Sorry. I broke my own rule about simple questions and answers. Sometimes I can't help it.