as an admin, i can assign a user-created group to a subforum. the group founder becomes a 'mini admin' of sorts, able to alter the colours, change the logo, ban users from their sub board, this sort of thing.
imo this is a great solution to two problems:
a. tedious intervention on subforums
b. unused usergroup threads.
what are the chances of this sort of functionality making its way into xenforo?