If that's the test [irreplaceable contribution], color all of us toast.
Not that any of us can be perfectly replicated as far as contributions go, but nobody here (or anywehre else in life) is irreplaceable as cogiator.
As for the rest of your post, I agree. "Who cares?" The fellow can come back or not, under a new handle if necessary. All of the ramifictions and baggage of being kicked are in play.
I wasn't implying that there should be an insurmountable standard erected for re-admittance, only that there was nothing so compelling or intriguing about this person that would merit such a request.
I guess if other people want to make a brief for him they're perfectly entitled to, but I agree with you in the sense that it's not much of an issue.
I just wanted to express my concern that other people would be willing to the mat for users who were rightfully banned, while not supporting other, much more worthy, cases.