Ogres playable on Horde. They're native to Draenor, an original Warcraft race, have always been primarily Horde and Blizz originally wanted to add them in Vanilla and then Cata but didn't so they're long over due, so it seems like a no-brainer.
High Elves playable on Alliance lead by Alleria most likely, since they've hinted a lot and flat out said that Alleria is going to play a part in the next expansion and Alleria is lost somewhere in Draenor so I predict High Elves for Alliance. Not as likely as Ogres on Horde, but I believe that Blizzard could change them enough to be different from Blood Elves with their lore/personality/style/models/animations and if you think about it, Ogres aren't that much different from Orcs.