I would like to see a menu (like in MMOs) where you can create and manage a clan and another where you can unificate 2 clans (or more) in an alliance, where you can talk, trade, etc And it would also be AMAZING if you can add a logo or image that identifies your clan from others.
It would be really cool as an in-game option. Though I think it's nearly just as good to have a part of the forum dedicated to clan events and such.
If it were possible to add a clan/group interface then I would not pass it up however that would bring the emphasis away from the forums; as Zeldo pointed out. Having a generalised clan hub that lists all the known clans and including some vital information about them would be a good idea too. For example the hub could list a clans total member count, allegiances (allies and enemies), whether or not it's a role-playing clan etc etc. This does then present the situation of having someone in charge of updating this information, unless it can be edited directly by presumably the Head of the clan who had submitted their information in the first place.