Aldriana has put up a Cataclysm FAQ
which goes into detail about raiding at 85. For anyone interested in raiding as a rogue I strongly advise you read this. Summary is as follows.
- No, you really can't play Subtlety. Early modeling shows it 5-10% behind Combat in DPS. While this will improve somewhat as raidwide crit rates rise, don't expect Subtlety to be competitive the way it has kinda been the past few weeks at 85, when everyone has roughly 1/3rd the crit chance that they do now.
- Assassination is the premiere DPS spec, offering the best single target DPS in any encounter in which it gets to DPS during Execute Range (i.e. a boss that 'dies' at 50% would see Assassination Rogues fall significantly behind, more on that in a moment), as well as the best target-rich AoE DPS (5+ for short lived targets - think Ony Whelps - if I understand what's going on correctly in terms of the modeling, as few as 3+ if they live long enough that using Deadly Poison on the thrown and keeping 5 stacks up is a viable proposition.)
- Glyphs are Backstab, Rupture, and Mutilate. Glyph of Vendetta is a terrible glyph if you are going to spend any time at all within execute range on your target. Do not use Glyph of Vendetta it is bad.
- The death of Combat is somewhat exaggerated. In terms of theoretical output, Combat is within 3% or so of Assassination, well within the territory where we can go back to the old saw "spec for the weapons you have, not for the weapons you want". In other words, it's not better to use a shitty dagger just to stay Mutilate when you have a good Sword/Mace/Axe/Fist available to you. Combat is also arguably better than Assassination if: you can get good use out of high Blade Flurry uptime, or there is a significant need for you to output your highest DPS before the boss reaches 35% HP. (Examples would include Heroic LK where P2 is the challenge, etc.)
- Glyphs are Sinister Strike, Adrenaline Rush, and Something. Something is probably Slice and Dice. Rupture and Revealing Strike are both possible contenders as well, but see below.
-The hilariously complicated Combat rotation can basically be ignored. The difference in DPS between using RvS and Rupture properly, and just ignoring both abilities is about 200 DPS. Yes, 200 DPS.
- Stat priorities: Agility Uber Alles. Basically, the best items are the ones that have the most Agility. Since generally every item of the same ilvl has the same amount of Agility, this can be reinterpreted as the best items are the ones that have the most sockets. Given equal numbers of sockets, the items with an Agility socket bonus that requires only Red gems, or +20/Yellow or blue gem are the best items. If this rule of thumb fails to help you decide, take the piece without crit rating, or, the piece with mastery for Mut, the piece with Haste for Combat. In general, secondary stats are sufficiently weak that you can basically run with one gearset for both specs. If you're seriously about min maxing every last bit, reforging when you respec is an option to cover the different priorities, but you can't go too far wrong just turning all your crit into Haste and calling it good for both specs in early running.
- In spite of my statements above about how Really, Combat is Pretty Okay, the fact is that given the nature of the actual encounters, Combat will often be not that okay. This has a lot to do with the fact that Bandit's Guile takes about 30 seconds to stack, and Redirect being on a 1 minute cooldown, and the specific timers in place on encounters where you'll need to do frequent hard swaps. The easy fix is for them to put Redirect on Restless Blades. Whether they'll do that, or something else, who knows.
- No, Wound Poison is not better DPS than Instant for Combat. It hasn't been since T8, and the loss of access to poison talents doesn't change that.