I'm not really sure what to expect really. As Skyward Sword is positioned way before Skyward Sword in the timeline, I'm expecting that due to the fact that Ganondorf doesn't really seem to be known in any events before Ocarina of Time that there will be a new villain, which I'm hoping there is. So I guess I could say that I'm expecting for there to be a new villain, but I feel that my reasoning lacks and solid ground to support itself on, which brings a lot of doubt into my expectations.
I really do not wish to see the return of any Zelda villains from the past, as I want to see someone that I've never seen before. I also hope that they don't do what they did with Ocarina of Time, which is introduce a new villain, but it turns out that he was just a mere pawn in Ganondorf's plans (although I'm not saying that was a bad thing). Considering that Skyward Sword looks like it is going to have a much lighter tone, I don't expect them to have the kind of cool, insane villain that Twilight Princess had with Zant. So really, a new, more sane villain would be ideal.