had a lil' idea
basically, there's a train going smack dab in the middle of the map, killing anything in its path
if you did a certain thing (capture a point?) you'd be able to stop the train and create a pseudo barrier across a path or something for about 30 secs until the barrier goes down and the train goes on its merry way
the train doesn't necessarily have to be in the middle, there could be 2 or 3 instead of just one
although the problem with this is that what if the train is moving as the point is captured and it collides in the middle of the barrier? plus the multitude of logic entities required in this...
if someone wants to team up with me to do this, i'd be alright with that (although i haven't got much to show, i still know my way around balancing and things, just not finishing things...)
just add me on steam, username is ProfHappycat