Donald Curry under Dave Gorman as manager should beat Cotto. But the Curry post-Gorman would be vulnerable to losing to Cotto (The 400 plus amateur fights Curry had was beginning to catch up with him.)
I think the answer is probably somebody like Ricky Hatton. Miguel Cotto simply wasn't very good compared to many elites of the past. There's so many fighters throughout history who would beat him that we could fill an entire thread of them.