In yesterday's changes to Warlords of Draenor we saw one of my most beloved spells be removed from a Warlock's demonology spec arsenal: Grimoire of Sacrifice. My Warlock relied on the Grimoire to take care of all his evil ministrations, and whenever he needed to kill something and get that blood urge out of him, his demon was always near by. It's amazing the thing never turned on him.
As far as the reasoning behind its removal, Blizzard has this to say:
Personally I think the change makes sense, even though I enjoy sacrificing my little demon. As to the Grimoire of Synergy, it makes sense too, but looks to be a lot less fun. It almost feels like an old-school talent too, which is interesting given Blizzard's move to get rid of straight up increases.
Update: Clarified that this is about the demonology spec.