They've said we won't be able to queue with more then a 5-person group at once.
But they've also said, we'll need to queue for rated BG's as a group equal to the number on your side.

Not sure if that means some kind of a rated interface, where you are matched with other groups of five/individual players who also wanted to queue for rated.
Or, more likely, you enter rated BG's as a raid... in which case 10 toons together is very possibly, and that non-rated BG's are a maximum of five, which means getting two boxers or ten toons together will be difficult if not impossible.