My theory is WOTA caverns of time expansion. I think Tyrande will be a major player in the next expansion, they are obviously saving her model update for something. Also we have heard nothing about the WOTA raid, did they decide theres simply too much for one dungeon? It would also give them chance to give Illidan some love seem as hes had such a poor showing in wow so far. And would allow them to spend time building up Azshara as a major villan for the maelstrom expansion