Just when we had mages and warlocks conditioned to roll on +spirit gear, and shaman chastised for even thinking about taking a piece with some on it, Blizz had to go and change up everything for Cataclysm. But not everyone has gotten the message yet. And some have gotten the wrong impression that +spirit is now exclusively a healing stat.
Here's the scoop.
Shadow Priests can and likely will take the Twisted Faith talent: Increases your shadow spell damage by 1/2%, and grants you spell hit rating equal to 50/100% of any Spirit gained from items or effects.
Holy and Discipline Priests have Meditation (Passive) - Allows 50% of your mana regeneration from Spirit to continue while in combat. Holy Priests also have the Holy Concentration talent which increases the amount of mana regeneration from Spirit while in combat by an additional 10/20%.
Mages have no spirit related talents.
Warlocks have no spirit related talents. Fel Armor no longer adds Spell Power from Spirit. Life Tap (and Glyph of Life Tap) no longer use Spirit for their various effects.
Balance Druids can and likely will take Balance of Power which increases nature and arcane spell damage by 1/2% and now increases spell hit rating by 50/100% of Spirit.
Restoration Druids have Meditation (Passive) - Allows 50% of your mana regeneration from Spirit to continue while in combat.
Elemental Shaman can and likely will take Elemental Precision which now increases your Fire Frost and Nature damage by 1/2/3% and grants you spell hit rating equal to 33/66/100% of any Spirit gained from items or effects.
Restoration Shaman now get Meditation (Passive) - Allows 50% of your mana regeneration from Spirit to continue while in combat.
Holy Paladins now get Meditation (Passive) - Allows 50% of your mana regeneration from Spirit to continue while in combat.
What This Means for Master Looters and Raid Leaders
At this point in the game, someone's undergeared alt may still see a +spirit piece as a major upgrade even if the spirit is a wasted stat for them. When you are comparing an ilvl 200 blue to a 232 epic, there is still likely a big upgrade there. But as of December 7, that's when things get hairy.
Once Cataclysm drops, a mage or a warlock grabbing a piece of spirit gear from a priest of any flavor is akin to a DPS spellcaster grabbing a piece with dodge or a healing proc on it or a healer pitching a fit over wanting a weapon with hit on it. Yes, they should have it if it would otherwise be DE'd, but they shouldn't be getting that item over the classes and specs that can actually use the spirit points.
The big question is, how do you want to handle the +hit gear? Yes, a shadow priest can use +hit. However, they are also able to gain hit fro the spirit gear for which they should now only be competing against other priests. It's too soon to know (having not seen all the potentially gear from Cataclysm) if a shadow priest could conceivably obtain all their BiS pieces and hit the 17% hit cap without donning any pieces of hit gear. But if that does turn out to be the case, you may want to strongly consider giving warlocks and mages priority on the +hit cloth gear. What to do about weapons remains to be seen as well, until we know how Blizzard is choosing to itemize them.
Why These Stat Changes Now?
Why did Blizzard throw this big spirit monkey wrench into everyone's gear bucket? All in the name of gear homogenization.
They didn't want to have to create relics specific to each class. Or to have endless flavors of trinkets and weapons and off hands to allow for the variations that existed previously from class-to-class performing the same role. If you play hybrids (which is almost exclusively what I play, and is exclusively what I've raided with) you've probably seen a number of times what a PITA it was to get the pieces that were right for you from an itemization standpoint, and often had to do some armor proficiency downranking to get them.
Hopefully, these changes will mean there won't be another restoration shaman raiding with the same bracers for 10 months (/wave at Emtox), and that boomkins can stop having to mix and match cloth and leather.