I want to take a moment a plug an interesting comment that I found on the WotLK shadow priest thread at Elitist Jerks. (Just so you know, 95% of the information conveyed in this comment is in the form of easy to understand charts. If math isn’t your thing, you will still be able to understand this post.)
Chart highlights (and my comments) below:
Using SimulationCraft, priest DPS in WotLK was compared against a handful of other classes (shaman, mages, and balance druids). The “ShadowVanilla” priest is how priests appeared prior to the WotLK changes, whereas the “Shadow” priest is how things stands in the beta now. Provided things don’t change (which we know they will), it looks like shadow priests will be competitive DPS-wise. Holy priest DPS is weak in comparison (as well expected).
My prior estimate that shadow priests could feasibly reach 4k DPS in WotLK raiding appears to be a reasonable assumption.
Mind Flay has considerably increased in its amount of damage done after the recent WotLK changes (allowing it to crit, increasing its spellpower coefficient from 57% to 85%, and allowing Misery to increase its damage). As things stand now in TBC, Mind Flay usually makes up about 1/3 of a shadow priest’s raid DPS. It is closer to 1/2 now.