Depends on what you define as ability. In terms of you put him on a random team and what's his impact? Probably around 15 or so seems right. In terms of completeness of the game? I think there's an argument to be made that he's the most all around complete player ever due to his size. He's a great shooter, great in transition, great in ISO, great off the ball, great shotblocker, excellent rebounder, very good passer(how many small forward have ever averaged 5 assists playing off the ball), and a very good man defender. I don't think you can really say there's something he can't at an all star level relative to his position. People that say he can't pass are prisoners of the moment and compare him to LeBron. LeBron is one of the greatest passers to ever play the game, remove him and Durant is arguably the best playmaker at the SF position in the league