How about things like 'electro-coils' to buy, then plant which electifies the enemy if it comes within a set distance (It would have to be limitted to a certain amount of shocks).
Also a water map where you have to take the bases in the middle of the water. Water could be accessed with jet-ski thingies instead of the hoverbikes.
Enclosed are some illistrations of my ideas which describe these ideas in further detail.