Going back in time, I remember this one athletic QB that did develop his passing game in such that he did have a long successful career. Randall Cunningham. Didn't hurt having Randy Moss and Chris Carter to throw to.
He didn't get really good till he injured his knee and had to sit the bench for a few years. When he got a a second chance his game had completely changed. That's a sign of a smart man and a true professional.