in reply to Old, unused nick desired..
*tiptoeing* on the subject as I don't know if I really have the authority/rep to comment on something this large, but...
I largely agree with what's been said. I'd like to say that Tye has the right idea about not deleting a username once someone has made a post. Deleting users who have made posts (correct me if i'm wrong) risks data corruption.
Unless you are willing to delete their posts and so forth, or come up with some kind of re-naming scheme, all of which seems rather undesireable.