I don't know if all these shadow priest here are trolling the shit out of me but i will explain it one more time: Shadow Word: Pain does X amount of damage instantly with no cooldown in MoP and WoD. Fel Flame does Y amount of damage instantly with no cooldown in MoP but will no longer exist in WoD. So what is the difference in terms of mobility between those two abilities so that one gets removed but the other one remains?