I'm a little late to this discussion, so I'm sorry if others have brought it up, but...
I really can't agree that Pierce is the best offensive player the Celtics ever had. Has to be larry, as his passing is so much better than pierce's and does count for offense. I'm pretty sure that Tommy was careful to say that he thought Pierce was the Celtics' greatest "Scorer," which is quite different from best offensive player. I think for "scorer" pierce may have a case, especially if you are considering one-on-one creativity, but for offensive player overall, no way.