the game gets far too unbalanced past 7v7, any higher and the aliens have a huge res disadvantage. All the marines need are a few good shots and some organization and they should really never lose at 8v8+
I'm not concerned about balance, I just don't like playing with such big teams. The whole game just gets less personal and more deathmatchy as you add players. 8v8 was the sweet spot, any more is really pushing it IMHO.
somehow I get same feeling about 9v9, and what Pie said.