Your build looks pretty decent as it is. I dont profess to be the end all of talent specs, but there are a few tweaks I would suggest.
Here is (roughly) what I would do. With preferential changes possible as noted below.
1st: It seems that you are holding onto some pvp talent points. Instant howl of terror being the primary one. This is super handy for pvp and arena, and when soloing large numbers of (non-elite) adds. In a raid, especially 25 mans. I dont think I've ever used this. If I were to dump these 2 points elsewhere, it would be either suppression, Imp. CoA, or (most likely) Amp Curse/CoExh for afflic tree - or improved immolate or demonic embrace for other trees.
2nd: You need to choose whether you want Ruin, or Unstable Affliction. Ruin is fun to see the big SB crits pop up (and super handy in pvp). However, and this is BIG - so will your threat! and thats not fun to see. UA will give you a more steady, consistent threat generation that is easier to manage and wont leave you standing there doing nothing for 30 seconds waiting for your threat to drop again so you can resume dps'ing - which will happen with big SB crits.
Here is a more consistent dps, and threat efficient RAID build. IMHO.
AmpC & CoExh is more pvp I know, but youd be surprised how handy the amp can come in when you need to kite something, or make things easier on someone else who needs to avoid a mob. You mentioned Gruuls and kara. A few things that come to mind already are Amp curse doom on curator, and Kiting tin man (earlier in fight b4 hes slow) or put on roar to give you more time to recast fear on his way back. Also the Maulgar fight has a boss that tends to be more mobile (cant remember name off top of head) and the slow tends to be a handy thing there at the right times.
Also suppression, although not really necessary, is handy. both to reduce the amount of hit you need as a deep afflic build, and to reduce those pesky full resists. (one in the same I know, but hey).
my 2 cents.
Cheers