Should anyone GOPer in the current "group" scare the Democrats?

[Xing]

Bush - His money is something to be scared of, if nothing else. In terms of substance, though, I'm not too worried. The only way he'd win without a very favorable environment is by buying his victory.
Christie - I'd be a bit nervous, but I doubt he'll win the nomination. Also, I could see the skeletons in his closet really hurting him.
Walker - A bit, but people really love overstating his victories. If he's battle-tested, so is Sherrod Brown, and yet I don't think Republicans would be terrified of him. Also, he's not a very polished speaker, and that would almost certainly be a liability.
Kasich - He scares me the most. He would not be easy to beat.
Paul - Honestly, not really. I don't think the GOP establishment would ever be behind him.
Rubio - This guy is kind of an amateur, I'm really not too worried about him.
Cruz - Don't make me laugh.
Huckabee - See Cruz.
Santorum - See Huckabee.
Perry - See Santorum.
Palin - See Perry.
Carson - See Palin.