1st off there has been no numbers tuning as of yet. So I'm posting any opinions on the basis of mechanics.
Fights I've seen so far:
Immerseus - Pretty clear to me burst on the adds is the key to the fight. Destro with Havoc cleave is the clear winner. Shadowburn to finish off low adds near the boss is an added bonus
Fallen Protectors - Assuming the bosses are tanked close to each other (in HoG or RoF range), all specs should be fine here.
Norushen - Reasonably sure the optimal strat will have warlocks focused on AoE for a large portion of the fight. All should be ok, demo and destro probably slightly better for when they need to burst adds down stairs (although redesigned soul swap will make this not terrible for affliction either)
Dark Shaman - Probably Demo?, affliction might be good as well. Hard to see destro performing all that well here. Bosses move a lot (making RoF useless even when they are tanked together), a lot of movement is required from players as well.
General Nazgrim - the AoE part at the start is stupid and inconsequential...I'm uncertain about this but Demo should be pretty good due to mobility, but if the adds don't live long enough for doom to matter, maybe affliction (with new soul swap) would be better. Destro should not be terrible either.
Post if you have thoughts on these or other bosses. Please say why you think a spec will be best
Turt, I agree with your thoughts on the specs. If there are any issues with killing the Foul Slime on Dark Shaman, I can see how Destro or Demo might assist for an easier burst of AOE compared to Affliction if required.
Back to this after a couple months more testing....I'll post my own larger guide/thoughts later on today or tomorrow (its almost ready), but in the meantime here is a quick list of spec's Evrelia posted as his feeling for optimal on each fight. I largely agree.
Immerseus - Destruction
Protectors - Affliction
Norushen - Affliction
Sha of Pride - Demo or Destro
Galakras - Destro
Iron Juggernaught - Affliction
Dark Shaman - Affliction or Destro - (Destro does better AoE, but an Ele sham is more preferable for that purpose and Aff is higher on bosses).
Nazgrim - Affliction
Malkorok - Affliction
Spoils - Destruction
Thok - Not decided, possibly Demo.
Siegecrafter - Affliction
Klaxxi - Affliction
Garrosh - Any spec could work depending on your strategy and your role within that. Demo offers the best overall DPS if you're able to stay in AoE range every time the waves are up. Destro is fantastic at killing the Siege Engineers quickly. Affli offers the highest boss dps.
Note: Demo doesn't appear much. That doesn't mean it sucks, it just means for each fight another spec choice is likely more optimal.
Like we talked about on mumble, the fights might have different demands from the dps. An example of that in the current tier is Durumu the Forgotten and the ice walls. For SoO a similar example would be the Dark Shaman because of the adds that spawn and the need for ranged burst aoe. While on the flip side some fights have no requirements, such as Ji-Kun.
Primarily I am thinking of playing Affliction / Demonology with the preparation of being Destruction.
Immersus: Affliction ; Destro
Sha of Pride: Affliction
Galakras: Affliction ; Destro
Dark Shaman: Affliction (Destro if adds need burst)