I swear, Grimm's plan to get me to 70 is centered around the core precept of "let's wear the priest out." I don't think I can even *bounce* right now. Getting in a full day of questing is impossible now; the XP bar goes purple a couple of hours in.
The good news: I'm 62 now. I've been through Scholomance, Hellfire Ramparts, and Blood Furnace now. In fact, we're going back in to BF tonight, if all goes well, because there is a certain robe that I need.
The deep Discipline (CRACK!) build is working out splendidly. Mana is of little concern unless I'm in the midst of a few dozen mobs. My DPS is around 275 at this point, which is satisfactory.
Healing is a whole new thing. We wiped numerous times last night in BF, although I really don't think anyone's laying that at the healers' feet - just bad pulls. As long as we got good pulls, I was able to keep up, even though it got frightening once or twice. And I'm missing certain tools from the Holy tree like the ever-popular Frisbee. But the key at this point is not so much to succeed as a healer, as to start learning the habits of a good healer, and reinforce them when possible with win.
My most difficult task is not to become distracted from my "healing trance", as I'll call it.
Well. 7 more levels, a dozen or so instances. Here's to future success.