Here is how i see it.
Offense is weighed more heavily than defense in the nba.
Tony allen... great defender, not a superstar. Same with sefalosha. Same with hibbert.
Even a two way player like marc gasol. Not a superstar.
I think you need to be able to carry a team in big games offensively to be a superstar for the most part. Paul pierce, kevin garnett, cp3, nowitski, kobe, wade, lebron, durant, iverson, are all guys that i have seen take over games on the offensive end in the playoffs and carry thier teams to victory.
Guys like irving, harden, lillard, curry, rose, westbrook etc are guys that i can picture carrying thier teams to victory in playoff games.
George is still young so its not like he cant get there (and im not saying that i would take lillard or irving over george right now) but right now i just cant imagine george scoring 20 pts in a 4th quarter playoff game to will his team to a win.