I can't tell how it will look in three dimensions. So, I couldn't tell you how to improve on it. Have you tried using google sketch-up?
You need to, as rusty said, use sketch up or go into forge and just make a basic version/layout for your map. Can't real help until then.
Ya like they said try Sketch Ip but from the looks of it I'm guessing it is going to be an MLG Map since it is symetrical and has MLG Weapons. But try Sketching it Up