Nobody likes main-camping.
Everybody like base building.
Restrict the one or two people's ability to go main-camp, forcing Combat Engineers to play strategically with their team on the objectives.
Give more freedom and space for players to build structures around the the objectives.
Inner radius; weapon emplacements, FOB's, Repair stations, ammo crates, HASCO towers/walls, indirect fire shelters
Outer radius; sandbags, ladders, barbwire, landmines
?