First they removed my favorite Warlock spell Shadowbolt and then they remove my SECOND favorite spell Drain Soul. Very disappointed to say the least.
They also removed Shadowflame last expansion which was a great spell for killing mobs while farming or soloing old content. At least we still had Fel Flame to sort of fill that roll, but that's gone too.
No more Soulshatter either. Wow... I can't wait to die to every other trash pull in LFR and Flex. Was Shoulshatter actually hurting anyone? What a joke.
edit: Some pros would be the level 100 talents. I'm really looking forward to trying them all out. Demonbolt, FnB Chaos Bolt, Cataclysm, perma Doomguard. They all look really fun