Wilt's problem was that he wasn't consumed by winning(much like Lebron). When he lead the league in assists, he did so because he wanted to lead the league in assists that year. He was probably the most dominating player to ever play the game, and if he cared more, its insane to imagine what he would've done. He was always compared to Bill Russell, and they duked it out, a lot. But I think Wilt took some pride in not letting winning or losing completely define him, he had other things in life he chose to do. Bill Russell would puke before games and just be utterly relentless and singleminded, much like Jordan and Larry Bird.
Oscar is often forgotten in the "greatest ever" discussion, and I think its because he was such an angry prick and a horrible teammate. Just an absolutely unbelievable player.