I think that there should be an option setting (in the same way that you can choose your game mode or set your party to open).
The options could be JOIN FAST which puts you into a game or lobby with almost no delay, you would have a fair chance of joining a game in progress after players have quit out and therefore you would join "losing" and "losing almost over" games, but you would sometimes join "winning" games and often lobbies between games.
The next option could be JOIN GAMES EARLY ONLY which would take out games over 50% played (by virtue of winning score or time elapsed). You should have a mandatory time delay here, perhaps 15 seconds to encourage players to use the first option - we want mass quit out games to be reinforced as soon as possible. It can also be a lot of fun coming in as a new trooper hero and turning the game around with a marginal win.
The third and last option could be JOIN UNSTARTED GAMES ONLY, the choice for serious-minded codders who want to keep their stats sacred and are happy to wait. Often this is worthwhile because you might only join once in a whole evening of COD. There should be a madatory wait of 30 seconds plus then you are placed into a newly formed lobby (perhaps brand new, perhaps recently formed by like-optioned players) and so there is a further time delay for a game.
