It will take a smart guy to beat him. Mayweather hasn't fought to many guys that are ring smart- the obvious exception being Marquez and the size differential there was huge. He fights a lot of guys that are good at throwing punches, but not so good at figuring out how to hit a guy that doesn't want to get hit, and knows how to avoid it. Another thing, smart fighters don't get hit with a lot of right hands (because you can see them coming forever) but dummies eat them like popcorn; James Toney had a real good run exploiting this same tactic, even as a weeble of a blown up MW.
"Knowing how to fight" is not a prerequisite of becoming a professional fighter; in fact, it is very very rare in this era of boxing. Mayweather controls the distance every time he fights and a guy that knows how to fight would contest that with him. It may not lead to an exciting fight, but that it the beginning of the way to beat him.