First, I like him. He lives in my town in the summer, and he seems like a nice guy.
Second, he's brilliant. If I needed a brilliant guy to do something for me that required a high IQ, I'd pick him.
Third, he's only a so-so politician. Politicians have to work comfortably with idiots and scumbags, he doesn't really do that well. He thinks politics is just another type of management, but the two domains are really different.
Fourth, and most important to what we're discussing, he disdains ideology. He's a Dole-ite in this regard ("nominate me and I can be whatever you want").
In conclusion, it is possible that, if the circumstances seem to actually require it AND the electorate demands it, he could function as a conservative President. But he has no anchor to windward, and given the titanic forces that will be in play as the welfare state finally dies, he'd be very likely to get rolled.
I see nothing that indicates brilliance. Above average IQ, perhaps, but IQ and wisdom are worlds apart.