Y'know, I think Mitt Romney is probably a terrific manager.
Putting aside (for the moment, anyway) exactly what kinds of things the company he was running actually did to be profitable, the consensus seems to be that he was really good at what he was doing. And I think he deserves some credit for taking over the '02 Olympics when it got into trouble (again, looking only at results, not details).
He certainly looks the part. I think, were I, in some alternate universe, a corporation director looking for a CEO, I'd look for someone much like Mitt Romney. He seems to be someone who has the competence to "pull the levers", as they say, of a large enterprise. To use a metaphor I've used for myself, he knows which buttons to push. He is, to use a somewhat obsolete term, a technocrat.
But here's the difference between a manager and a leader: a leader can hire a good manager. A manager, however, can't hire a leader. Indeed, almost by definition, one cannot "hire" a leader.
Mitt Romney: Decent guy, probably more personable than he seems, helluva manager.
But, ultimately, not a leader.