Heya,
I will be going for a mix, imo u go oom 2 fast if u go full full crit; I'll take the mooncloth (spirit) set.
I think the 4 piece bonus is 2 important in 2s atleast, for 3s 3x mooncloth + 2 satin is an alternative. If u take full satin, it gives u around 6% extra crit, but u lose alot of spirit and spirit give sp as well right, thats why im gonna go hybridish.
But still u wanna do dmg as sp, thus ur kinda forced to stack a bit crit this season (later full haste for extra dot ticks too, but u can't get 2 extra ones this season if u dont wanna play with ALOT of pve). I'll go full crit offsets (even neck/cloak), calculation is around 2% crit vs 3% haste. No big difference, but I'll pref the crit here.
Will be using PvE Rings -> Spirit / Haste Ring (213) from valor marks and preferably the Naxx25s Kel'thuzad Ring. Alternatively u can go Naxx25s Kel'Thuzad Ring and Honor Hit Ring.
@ Hit: I was planning on going for 3% hit on gear (Naxx25s Trinket + 1 SP/Hit Gem) which makes 6% hit with shadow talent without applying any debuff (theoreticly u have 6% without any hitgear as shadow, but that implies that e.g. ur fears may miss more often without dotting them first). 10% hit is hardcap in pvp, but going that far is overkill imo (ud/b11 rogues & pallies).
Trinkets that I will probably use -> Naxx25s Crit + Shadowbolt Procc Trinket & Hit + SP on Procc Trinket. There are a few alternatives like Naxx10 SP and Haste Procc, but I think I'll stick with those 2 (I love to shadowbolt as SP :D).
Hope that helps! (was also wondering about SP itemization, so I hope there will be more feedback on this!)
Edit: Oh and don't forget Spellpenetration -> 3 Blue gems (gloves, belt, pants) + cloak enchants = 95, to counter pally auras, mages, other priests if u don't have the time to dispell -> deadly spell penetration wand gives u 26 which helps u against most things.