From what i have read, it sounds like Brink will have some type of objective based game play, similar to W:ET and ET:QW Hopefully this is the case because it’s a huge part of what makes those games so great.
That being said, and assuming one side has to defend and the other to assault, it’s easy to get a map which favors either offense or defense. One way i think this could be addressed would be by having variable map times, based on historic win/loss rations. If defense is winning a disproportionate number of maps, the map time is extended, if assaulting team wins more often, may default time is shortened.
Maybe there could be some kind of weekly update from the master server which tweaks the map times or something?
This should help stacking on maps which end up favoring one side or the other.
just a thought…

and dont want to play that long. Secondly, if a team gets held for 40 minutes… it means that the only way they can make a comeback and equalise is if they also hold for 40 minutes. While that may be highly unlikely, its simply too long.