in my opinion, bigcity is the penultimate sandbox war map as it features everything you'd need for the gamemode, few interiors which allow chokepoints and bases to be build easily, a large skybox which allows for air vehicles to prosper, a huge arena in the spawn area where all the wars usually occur, plenty of roads for racing or otherwise, tall and large buildings that snipers can perch up on or for helicopters to land, garages for building or customisation, or otherwise.