i have to say this is a bad idea of limiting only to 12 BB. its taken a lot of the challange/fun out of GB's. i also just had a game with 1 BB6 in the room..he totally owned the whole game.
What makes more sense to me is leaving the GB rooms as they were, and perhaps limit the amount of BB6/EBB6 to 4 max...that would be a fun room to play.
More to my point , its the amount of BB6 / EBB6 that have been ruining the games of recent. these ships were made to fight against each other..not against lower lvl BB's which have little chance. A well piloted BB6/ EBB6 can push into 3+ enemy BB's and sink them all easy.
So in your new room we have 12 BB - 6 per side . 3 go north / 3 go south , 1 BB6/EBB6 can just roll over 3 BB with ease, thus making the problem only worst than it already is..IMO