Yeah, it's a little too early. Like five days too early. Ask me after HIAC. Seriously, I'm not sure where they're headed with their storylines even enough to be sure who's going to even be IN the match.
But OK, let's play make-believe. Let's say that all of the people you mentioned are in the RRumble and don't have belts. If he hasn't gotten a belt by then, I'd have to say Dolph Ziggler. With Wade Barrett being a close second, maybe tied with Ryback. Again, that's ASSUMING that none of them have belts at that point. And you know what happens when you assume ... you make an a** out of u and me. But mostly u.
On second thought, actually, Ryback would be a better choice than Barrett, unless they (a) do some big push with Barrett and (b) tone down Ryback. Realistically (or as realistically as studio wrestling gets), if Ryback is still seen as the unstoppable monster, then he'll either win, no problems, or everybody (heel, face, tweener, camera dude, etc) is going to gang up on him and toss him out of the ring. If they push Barrett and give Ryback a loss or two, then Barrett could be believable.
OTOH, I'm just really marking for Ziggler as of late. Despite his pathetic performance against Ryback on Main Event. I think WWE is gearing him up for a main event push, and the RRumble could be his ticket. So maybe ... which wrestler do I see winning if everybody is in the match sans title? Ryback. Which wrestler do I think SHOULD win? Ziggler.
However, I think HIAC is going to see a few titles change hands. At the very least, three title changes. The WHC will change twice (Show takes it from Sheamus, Ziggler takes it from Show ... in 34 seconds), the tag titles will change (Scholars take it from Hell No). The WWE title is one I'm honestly ... well, I don't know what's going to happen. And you know what? I like that!
Even more than thinking I know and being surprised, I like the idea that I'm really not sure what's going to happen. I mean, I could be wrong about everything else I say, but at least I'm certain when I say it. I've gotta give props to WWE for that, they've actually got me interested in this PPV, can't wait to see what happens.