In the trenches it would be nice to have some wooden boards or somthing down on the floor because last game it was turning into a near swamp and everyones boots were either sinking or slipping everywhere.

And also how about a sunken bunker in the middle of the game zone to add an extra level into the game to turn the capture the flag games and so on into a bigger fire fight. or create a whole new game
sort of like this
http://www.youtube.com/watch?v=yIlJSuFpSFQ
plus a few hut type things to set up roadblocks and things to put more challange to both sides