My recommendation is 2v2 with players seated opposite each other. Usually forces everyone to get involved quickly or your team might get smashed in a 2v1. If everyone is on their own it generally becomes more of a stalemate.
I heard of a variant where you win only if you destroy the player on your left (or right). That way everyone has a different player they are attacking and defending against and it helps with the everyone-against-one-player situation.
Not sure how that plays out as I haven't tried it, but I'm interested.