I was going to ask a similar question. I sat in the queue for ages last night with no pop. I got fed up and just queued randoms. It would be better if we could queue random and the brawl at the same time.
I don't think enough 20 - 29's will queue the brawl which is sad as I for one welcome some fun changes to old bg's.
I hope it does pick up popularity so we can get some going when they're up. Probably doesn't help that the last one was broken for low levels and most probably some won't even try and queue this time round!