If it's any consolation Elegon is more annoying than ever to kill since 5.2. Hope that Blizzard fixes whatever they changed related to that encounter so that I can go back to my 20 FPS on 25 man instead of 1 FPS now. Before you mention addons or reseting my UI, I've done that and it still drops to 1-3 FPS during the fight while in the central part of the room with Elegon.