Allen Iverson isn't so different from Paul Pierce, you know. Besides the obvious fact that Paul is by far the better team leader, the more successful player, has won a ring, isn't a distraction to his teammates, etc.
If you all still remember, Paul Pierce used to play shooting guard until Ray Allen was traded here, and since then he has switched to shooting forward. Now, that may not seem like such a big deal at first, however you can also look at a move like that as sort of 'going up a weight-class' as far as who Pierce now guards and is required to score over. Pierce is 6'7", compared to Ray's 6'5" and Iverson's 6''0" so it's not like that was such a difficult transition to make for Paul, though now Pierce is required to guard guys like Josh Smith, LeBron James, Tracy McGrady, Carmelo Anthony, etc instead of guys like Gilbert Arenas, Dwayne Wade, Kobe Bryant, Boris Diaw, Rip Hamilton, and so on.
Iverson, on the other hand has been an under-sized shooting guard his entire career, and has compensated for this by stat-stuffing. Even when he starts in the All-star game, he almost always plays point-guard there so I have found it disturbing how other teams in the league haven't found a way to properly utilize him as a pg yet. He averages more assists per game that some starting point guards in the league right now and would be instantly effective on teams like the Miami Heat or the New York Knicks. Even the two teams that shunned him in favor of 'younger talent' (Detroit and Memphis) could have benefited from AI's ball-handling skills and play-making ability.