The race of the worgen on the Alliance? Worgens are just too evil to be on the good side.
Goblins on horde might not be too bad. I can see Goblins vs Gnomes in a midget arena!
But the best would be Ursa for Alliance and Worgen for Horde. Battle of the Beasts!!!
Centaurs and Murlocs could also be in it. Hell why not make a 3rd Faction. A faction of Centarus, Murlocs, Worgen, Satyr, Magnataur etc. The faction could be called the Wild Ones lol.
What I wanted to see was the nerubian race join the Horde though. Nerubians would be awesome!!!!!
Or bringing in the PANDARENS just for the China market would be the ultimate move!!!! (http://www.wowwiki.com/Pandaren) Panda force!!!!!!