Originally Posted by
Sensui06
1: The Alliance imprison him in Dalaran and have him stand trial for his war crimes.
2: The Horde imprison him with the darkspear being his jailors for his attempted genocide of them
3: He is sent to pandaria and imprisoned and watched over by the shado-pan. He did after all destroy their sacred vale.
Of all those i say three is the most likely as i could see in patch 5.5 a small quest chain showing the alliance and horde arguing over who should get him. Taran Zhu steps in and tells them the shado-pan will take him and keep watch over him the rest of his days to insure the cycle of reprisals ends. They would also be the most likely to treat him fairly and most able to deal with the lingering sha/old god corruption should it manifest.