At his peak he was a top 10 player for probably 6-7 years. And had a lot of good years besides that.
They let a lot of guys in who have longevity but were never really top 10 players, I don't mind valuing peak more. It is supposed to be a museum, if you look back in 20 years and Vince Carter and Mitch Richmond are in but Grant Hill and Tmac aren't, that seems backwards.
As far as team success, a lot of team success is based on circumstance. He went to Orlando and then G Hill immediately died and he was stuck for 4 years. If he played his last 4 good years with Kevin Garnett and Ray Allen like Paul Pierce did, he would probably be remembered a lot differently.
Chris Webber also considered overrated by a lot of people, really if you look at his career, he was an elite player for a shorter period of time than TMac. Basically only for 3-4 years in Sacto before the knee injury. But that was a relevant team and he was 1 of the best players in the league at the time. Should be in (and it factors in his college career as well but that is a different discussion)