I am sorry, but it would require a lot of editing to make such a thing possible.
The way websites work they have lot's of limits.
Everything is linked together: users to their comments, pictures to profiles, comments to threads
Severing one link will cause errors in other objects
For example, what will happen to the posts made with the account that has been deleted?
Do they also get deleted? Creating gaps in threads.
Does the user change into a [deleted user] profile? Creating entire threads with nothing but [deleted user]'s talking to each other.
Do they transfer over to the new user using that name? Giving them power over editing the old users posts.
Do they keep their profile and allow new users to choose the same name? Making threads with same name users claiming different things as they are different users.
There are more complications to freeing names than just deleting some text.
This has to be thought out before it could be implemented.
Like with Facebook. If you try to delete your profile it doesn't delete it but instead disables the account.
Your posts will still be linked to your disabled account and if you decide to come back after 5 years, you can simply re-enable it like nothing happened.
