This was my Z's heal spec. Blessing of Chaos, Tzeentch's Grip, and Restorative Burst are pretty much mandatory. I prefer Morale pump to flash heal, and I prefer'd the AoE HoT to the AP ritual. RP AP ritual works on all abilites, Zs only on attacks. Depends on your group though. And, I haven't played Z with the new AP changes, so maybe that Ritual is mandatory now... Also, with the Morale changes inc, it's possible that the morale pump is utterly worthless w/o a Core M4. Dunno, people will have to test once that change is made.
For lvling up,
This was my farming spec. With it, I could farm approx 1mil XP worth of mobs per hour. You can avg 8-12 Mobs at a time, constantly. Cycle between M2 Siphon, AoE Punt and Embrace the Warp everytime you start to get low, spam Spittle , Rite of Agony, and Chaotic Agitation for much profit. I avg'd well over 100g per hour just worth of greens and crap to sell. Before I scavenged/salvaged or sold any blues/purp drops...
Technically you can start solo farming from 27 with
This and much better at 31 with
This. It's a bit more difficult w/o Chaotic Agitation, but you can still make it work quite well.
previous to 27, you'll be MUCH better off finding a buddy to heal that can pump out real DPS...
And don't take what anyone has to say as Gospel. The best thing you can do is try a few different specs, and find one you enjoy and fits your style/group. Warping the Spirit can be GREAT, as can the Flash crit tactic along with Endless Gifts Cleanse CD reduction. There is no one Spec to rule them all with Z.
Just have fun:P
RR depends what you are doing. PvE mobbing, go full Parry. PvP full Deft Defender then lower your chance to be crit. Zs can be super tanky, utilize that.
p.s. If you have AP issues, wait literally 1/2 a second between casts. Don't spam the button between instant casts. Your overall heals/minute will increase drastically. Also, buy AP Pots... Or group with a DoK with Restored Motivation or a Chosen with Dreadful Terror etc...
p.p.s. Healers currently don't have a functional Core M4. yes, Tzeentch's scream looks great, but you MURDER your spec to get it(and middle tree is for DPS spec mostly). But as I said, go for the spec you enjoy:P