Ysera being such a big name ingame and in the story, i would be so sad if she came back for no reason at all. Her return needs to be big, epic and life changing for the game. Her presence needs to be known.Make her return something extra
A nice summary here. I feel a bit better with this.
I have a weird feeling that Illidan will come back in a future expansion and Tyrande will set him on an impossible task to rescue Malfurion from Ardenweald