I'm not sure Fletcher can improve, tbh. He's not the youngest and seems to lack any of the explosiveness or speed needed to make him properly dangerous on his feet. His ground game is average.
Some fighters you can kind of tell they lack talent. They're hard working, love fighting, want to make a life out of it, but just have a low ceiling. Someone like Bones could probably have been shit hot at a hell of a lot of sports, the guy just has talent.
Fletcher not so much
Supporting - Machida, Edgar, Mitrione, Pickett, Cruickshank, Wiman, Lauzon, Falcao, Belcher, Korean Zombie, Palhares, Hendricks
Retirees - Lytle, BJ Penn, Hackney,