I would like to see a club feature, however I think it may be to many work for the 3.1.0 edition, and it would be better as a modification.
If you don't know exactly what I mean, take a look here: http://www.phpbb.com/community/viewtopi ... &t=1847275
A club feature is a feature where users can create groups like those on VBulletin.
You can have clubs which require a password to join, our an invite. A club can have a leader, who is able to delete the club...
For more features, view the link above.