It could be just me, but I do not trust him.
He has a questionable power from questionable sources (Deathwing). I never feel like he is telling us everything. True he is helping us to a great extent in Pandaria however his presence on Timeless so close to that bronze dragon (forgot his name sry) leads me to question his motives again.
What if he aided us to get rid off Mogu and Sha just to gain more power for himself.
What if by going back in time in WoD he plans to aid Garrosh and/or Deathwing?