Both are at their prime.
The Fight takes place outside of Orgrimmar And it's the Zandalari that are laying a siege towards the front gate of Orgrimmar and the Darkspear rebellion and the Alliance are not involved.
The Mogu do not help the Zandalari with the siege in person because the Mogu are part of a different faction (Mogu Empire). But they do get what power ups they were gifted with from the Mogu such as Jin'rokh.
So who would win?