I think you are underestimating the "American Idol" voter mentality of today. You must remember the primaries with those neon podiums, flashing lights, and 30 second time limits. I swear for a minute I thought I was watching some talent show. Rand Paul has that JFK look, with the pretty wife that America loves! This stupid crap wins elections now more than ever. Watching friends of mine hear Ron speak, have NOTHING to say about what they just heard, but instead making fun of him for his suit jacket which "doesn't fit his shoulders right and makes him look even smaller" drove this point home for me.
Because he is working through the Republican Party and wishes to have the GOP voter base support him. His positions are radically different from Romney's. And, if you've been paying attention, his performance in the Senate has been nothing short of heroic and anti-establishment.
Given the lack of real power from a VP, I wouldn't mind seeing Jim DeMint as VP, because his soft stand on principle will be mostly irrelevant, and he's retiring anyway so we won't lose anything from the Senate, and a LOT of mainstream conservatives love him so he's pick us up a lot of votes.