Insane person,
Evacuating casualties would be cool. It's a huge part of fighting doctrine of some countries. Getting casualties out quickly is a big deal, especially in a modern setting. You'd have to either get a vehicle to the injured and move to the edge of the map (losing the vehicle) or you'd call in a chopper, pop colored smoke, etc. Without evacuation capabilities, you would have to gather the wounded into a safe spot and guard them. Would be kind of cool to ads that element to the game.
Speaking of choppers, modern settings would include not only medevac choppers but reinforcements could arrive anywhere on map. The advantages might be offset by the danger of losing chipper and all passengers to enemy fire.