In that podcast where Bruce Feldman talked about Frost missing the meeting in Ireland, he made an interesting argument about why Frost worked at UCF but not NU. He said O'Leary was an asshole and very strict, and the players had chafed at that. Frost came in with a looser style and the guys responded and he got them to do what he wanted.
But when he came to NU, he stepped into a situation where the previous coach had already been loose. Frost didn't have the skill set to run something with more discipline, so he plopped his loose culture on top of one that was already loose and the thing became a disorganized mess.
So I don't know what he would've stepped into at UF. They always have talent. McElwain seems like an asshole, but also a fucking weirdo, so I have no idea what sort of culture was there. But maybe what he came into would have made a difference.