Sagan is in the top 5-10 contenders in just about every race situation that doesn't include a lot of climbing. The problem is, he's not one of the top 2-3 guys in any race. He needs a good team and some clever racing and I'm sure he can be successful, but currently there is always someone better than him at the required specialism when it comes down to the line, be that a pure sprint, an uphill finish, a break and hold it etc.