Affliction was nerfed at the start of Ulduar and destro was buffed. A few days after ulduar came out they also nerfed conflagarate because it was doing absurd damage
. That first week was really fun playing a warlock though.
Affliction should be fine, this GoSac nerf also nerfs our scaling slightly. Top end raiding as a Warlock next tier prob won't be pick one spec and play it for every fight. In a patchwerk style fight it appears Demo > Affi > Destro atm, but not by much. You can expect fight mechanics will dictate which spec is best, and that seems pretty balanced to me.
If you want to just play affliction for every fight, you can prob get away with it. It just won't be the most "optimal"