Moreover, although some of the tribal leaders have been willing to switch allegiance at the drop of a hat, that isn't true of the real fanatics. They are still showing that they are willing to die for the cause.
I am more inclined to agree with your general evaluation. We have been assuming that Bush would want to produce Bin Laden's body, but as you say there may be advantages in having him simply disappear. If he is already dead, there are also advantages in not saying so until after the whole country has been mopped up. He is a useful bogie to placate weenie-whiny liberal newspersons with. In fact, although he did nothing about the problem, it was clinton who first made bin Laden infamous, demonizing him in the clintonoid media, as had earlier been done with Saddam. So Bush already had a liberal-certified liberal demon to deal with, and that made it awkward for the press to complain.
If his body is never produced, anybody could committ a terrorist act and "blame it on Osama".