Fel Domination (http://ptr.wowhead.com/?spell=18708) A 3 min cooldown makes this interesting. A demon spec warlock could summon an imp for Phase 1 of the Yogg-Saron fight, then a Felguard for phase 2, and a Felguard or Imp for phase 3.
Pandemic now increases the critical strike damage bonus of your Haunt spell by 100%. Not a huge deal for Affliction warlocks, but DPS boost is a DPS boost.
The Fire and Brimstone damage boost by your Incinerate and Chaos Bolt spells to targets afflicted by your Immolate of 10% is a reduction. It is a nerf but not as bad as the forum crying would make you think.
Empowered Imp is awesome. It went from "critical hits done by your Imp have a 100% chance to increase your spell critical hit chance for your next spell by 20%" to a 100% chance. This makes up for any loss of the Fire and Brimstone effect.
Side note: Glyph of Life Tap lasts for 40s now. Vitandus can hook you up if you don't already have one.
All sweet stuff. It remains to be seen if the Empowered Imp improvement will make up for the F&B nerf. Since Incinerate is a Destruction lock's most often casted spell and Chaos Bolt is one of the hardest hitting spells, that could amount to quite a nerf. However with the change to Empowered Imp it will be very nasty indeed and may more than make up for it. I think this will be the case.
I may dual spec Affliction/Demonology.
I'm sticking with Destro/Affl