In a way it makes sense as a 'balance' for us killing Garrosh, to have Varian die. I so badly hope that next x-pac is a direct attack from the Burning Legion.
Oh man... do you know the kind of chill I would get up my spine if there was some intense cinematic where Anduin is shit talking some Legion big bad and enters Shadowform just as he starts forward to attack? Just the sound of him entering Shadowform mid-cutscene would be the shit.