Another point I would like to add: If Mogu can’t be a neutral race, we could get Mogu (Rajani) for the Alliance and Ogres for the Horde. So we could get two races coming from an old empire lead by an emperor.
Mogu (Rajani) could make a new “destiny” for the Mogu in the Alliance with other titan-forged races but also for the ones wanting to serve the will of the titans again. Meanwhile the Ogres could make a new clan (Stonemaul, Dunemaul and Ogres coming from WoD) in the Horde and try to make a new Goria on Azeroth as new capital (Stonemaul keeping theirs villages in Dustwallow Marsh).
If you want to know more about Mogu, feel free to check my thread about Mogu 
For me, Ogres could be playable for the Horde meanwhile the Alliance could get Broken/Krokul or Mogu. I think it could a good choice for the both sides if we need to choose a race for the Alliance if the Horde must get Ogres as playable race.