Well, according to the trailer Alistair will be there, but as what is yet to see. Doubt he'll be a companion. If he is king, he's probably there to help out in other ways.
I think Oghren has great potential. If you read all your epilogues, Oghren always straightens up, hell, in one he even named his child after my PC. (I like Oghren alot after that) \\o

He used to be the best warrior in Orzammar and highly respected, it's just that he started tumbling down hill when his wife left him for a suicide mission. Poor Oghren, I don't blame him for drinking.
But my point is that YOU are the changing point in his life, YOU are the one that gets him back on the right track. You basically save his life. And I highly doubt he'll be a drunken bastard in Awakening, but he will probably have the same humor
Besides, he is the only one that can return that's not also mixed up in the whole romance thing, unlike Ali, Leli and Zev. So Oghren is static, no matter your past, you were always just his friend, perhaps that is one of the reasons Bioware picked him out of all the possible ones. And let's face it, dog would be a boring returning char, as he can't talk or do anything besides ****** on trees and maul your enemies faces.
IF oggy is the returning companion, give the dorf a chance, I bet he will be awesome!