I guess I'm surprised with some names, like Webber and Iverson. Maybe we all have different definitions of the "disappointment." So I looked it up on dictionary.com. Disappointment really just led me to disappointing, which was defined as "failing to fulfill one's hopes or expectations." So what did you guys really expect from Iverson? NBA MVP, 11x All-Star, , 2x All-Star MVP, 7x All-NBA, Top 5 in scoring 8x's (leading the league 4x's), Top 5 in steals 7x's (leading the league 3x's). Finals Appearance. All over a 14 year career. And you guys are disappointed with this body of work? Maybe a first ballot HOFer? (probably some debate on this, actually it would be interesting to see a poll). I really think Iverson overachieved, the exact opposite of a disappointment. I remember how many arguments there were that Iverson shouldn't even be selected #1, no 6' player has ever been drafted that high, he was too small, too out of control, etc. I doubt even Iverson's strongest supporters would have predicted the resume he ended up with. Are you guys really calling him a disappointment?
And same thing with Webber. 5x All-Star, 5x All-NBA, 20.1ppg, 9.5rpg, 4.1apg, 1.4spg, 1.4bpg over a 15 year career, and the centerpiece of one of the best teams in the NBA for a 4-5 year span (who conspiracy theorists believe should have had at least one NBA title). Maybe expectations were a little higher with Webber, most probably thought he'd be a 10x All-Star, MVP, etc, but he did have a run as one of the best players in the NBA. So he didn't end up as one of the best PF's ever, there can only be so many of those. Maybe the title is thrown around a little too easily causing some disappointment when a player doesn't live up to those lofty expectations, but come on now. McHale was supposed to be the best PF ever, then Barkley and Malone, then Derrick Coleman (who I agree is a legitimate disappointment), then Webber/Sheed, then Duncan/Garnett, etc. It's like some people throw out "next best (fill in position here) ever" like movies get reviewed with "best movie of the year." (When you have 20 "best movies of the year" it kind of loses it's credibility).
All in all, I would say Iverson overachieved and Webber probably slightly underachieved, but I can't see how either can be considered the biggest disappointment ever.
(and when I say All NBA I include 1st, 2nd, and 3rd team).