I know Brad asked for ideas on how we'd like to see this implemented somewhere else, but the thread is buried somewhere, but here's my ideas for this:
1) Need to add a lobby for pantheon. This way people could chat and set up groups if they don't have a set group of friends.
2) Need to add a friends list option like SOASE has
3) Need to add a form group option from the lobby. Whoever forms said group would be designated as the group leader and gets to press the fight button when he has everyone he wants in the group.
Fairly simple in idea I think, you'd still get matched up against random people/groups of the same size.