Is a hell of a fun fight. Please do not nerf, it is amazing the way it is. Wish more fights were like this. Phase 2, you need perfect awareness of where you are and where the objects in the room are to get through this, fun fun fun fun.
Yeah, it's great. Let's not forget that Gravity spawn animation is shared by trinket proc, orbs/flamestrikes tend to spawn next to Tornado/Gravity - which, in turn, appear next to wall or other hard to reach place - , you're supposed to interrupt 1s cast that cannot be slowed, you'll get Lightning Rod just as you're about to change debuffs, that crucial fire zone will appear on other side of the room and having more than 1 flamestrike up = wipe. Also, phase 1 is a joke and phase 3 is same thing as normal, except 50% longer with 50% more damage.
E: Oh, I forgot to mention that Quake/Thundershock do >130k damage. You can't ignore debuffs like you could in normal and if you do, any additional damage you take after AOE will kill you. Assuming you even survive.
Perhaps 10 man is much easier. I find 25 man annoying as hell, especially since loot is pretty bad. After killing them, Cho'gall/Nef were a joke.
This was probably my favorite fight of this tier because it has some nice retard checks in phase 2(looking at you frost beacon) and is also a significant gear check in phase 3.