Any kind of objective mode would be great. Unfortunately it also requires servers to run a seperate server just for the different game mode and its maps. Something not well supported in other mods so far..
It can be done, now I played too much PR but it has a VIP (Xtract) mode where one side has to pick up for example a pilot kit to simulate a downed pilot. Then they mut escort him back to the main base flagpole. I imagine the code can be changed abit so the target just have to stay alive until the enemy is defeated.