I thought I should enter my first post (opinion) about priests.
Shackle (The undead CC)
I remember using this as a form of CC when doing undead Deadmines. By removing one mob attacking the main tank (MT), you will have an easier time healing the party. Aside from Karazhan, I only remember Sethekk Halls as the other spot to help control the amount of attackers. Don't forget that shackle is another option of CC. Mind control is good but it takes you out of the battle.
Discipline (alternate solo spec at level 50+)
Shadow is definetly the number one solo spec for a priest. However it leaves the priest short on healing capabilities when doing dungeons after BRD. When I heard the discipline route, I decided to give that a whirl. When going down this path, be sure to be able to get all the way to "Reflective Shield". Combined with this porcupine bubble and wand specialization, a priest can DPS thru most regular quest mobs. Downside is that mana regen is slow if low on spirit and you used a lot of spells. If the solo holy warrior is your playstyle make sure to combo it with Divine Spirit and Spirit Tap.
Circle of Healing (CoH) vs Divine Spirit
After watching several priests use CoH in raid fights, I was seriously impressed. When I tried it the healing didn't even come close to what I saw. This talent spell is really conditional and is not meant to be spammed (unless you have special trinket,etc). Plus it was mentioned in wikis that CoH heal bonus only improves after the 1338 healing power mark. By taking CoH, priest have to give up on Divine Spirit. I think Divine Spirit is a much better talent buff for priests (+50 spirit and +10% spell dmg).
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