Underrated is being used loosely in this thread... a few of these players have been give lots of praise and credit for the things they did in the league - it's just that more time has passed and they're talked about less.
A few that I agree are truly underrated: Pistol, Moses, McHale, Bernard King, Kevin Johnson & Baylor...
But guys like Isiah Thomas and Hakeem Olajuwon are not overrated. They are given plenty of praise. Thomas just manages to play down his amazing career by doing bone-headed things as a coach & executive.
"that is greatness right there, you can't stop greatness" - Charles Barkley on Kobe Bryant, 2010 WCFs