This is completely ridiculous... of the past 15 game I have played in multiplayer, all 15 of them have ended with me or someone else minidumping. Game length does not matter that much, although it seems I MD more often in the first 30 minutes of a game (might be because few games last beyond that).
I don't think I will play any more matches until Ironclad fixes this problem. It is completely ruining the multiplayer experience by throwing away a 1-2 hour game.