As someone who is not a fan of the President, I don't see any way at all that any of the top 3 Republicans can beat him next time around. I think Huckabee would come closest, because he's more believeable than Romney and he's not a trainwreck like Palin; and I think he's far more genuine a candidate than Romney, Palin or Obama all put together. But he can't win on a national level.
The Republicans need to search real hard for a candidate that can win.
I think you hit the nail on the head. Palin is a wackjob, and Romney doesn't seem very trustworthy, plus him being a mormon is a big handicap. Huckabee is the best out of the three, although I vehemently disagree with him he's a very honest and likeable guy