I think, just to make it easier to set up team battles and the like, that it would be a good idea to have a section where we have a list of all the teams and who is on them. This way, teams can easily find one another, know who is on each team, and see that teams rank, wins/losses, etc.
not a place to declare a team battle, just to view. And you can give the team leader rights to edit the section, for when players come or go, or whatever.