I would say Aldo, but only because he is going to move up a weight division first.
Preferably after defeating Edgar and Korean Zombie, he will move up to lightweight and have a tune up fight before fighting the lightweight champion. Imagine Diaz vs Aldo...man. Then Edgar can get the featherweight belt and dominate for a long long time.
Anderson Silva ♔
Aldo - Dos Anjos - Mayday - Weidman - Machida - Jones