I highly doubt the goblins would choose side. Their entire modus operandi seems to be "sell to the highest bidder". They don't care about politics or ethics in any way. They're like the Ferengi in that way. Choosing sides in a 2 sided battle would drastically cut their profits. Not only would they lose out on half their clients, they would also lose the chance for bidding wars.

As for the Worgen, well, I don't think I like that idea. I never really liked the Frenzyheart worgen style (the original ones, like the ones you see in Duskwood, are much cooler), and the Frenzyheart worgen are the only ones who aren't shown to be evil. The others are tied in with Archmage Arugal or the Black Riders and the Scythe of Elune, and, yeah, seem to be completely evil.

I would like to see the Pandarans. Pandaria is an as-yet unexplored area. Supposedly in Northrend, yet we've seen no sign of it, nor even any undead Pandarans. I doubt they'll be a playable race though, as whichever faction did not get them would be very upset, and rightfully so.

For Pandaria!