And even guessing that, since the New Horde is in a state of "rebuilding" similar to the one the Old Horde had after the Second War, Thrall could be fitting, the problem could be Thrall himself, and what the guy truly wants: at this point is very hard see him as the Warchief of the Horde again with all the development he had until now. Going to Orgrimmar, face Garrosh and put an end to the madness that plagued his Horde, all started by a personal mistake? That was logical, and he was absolutely needed there. But then feeling comfortable in be the Warchief again? I don't know, I have very strong doubts about it.