you should try to stay away from adding things that come out of the ground randomly add structure that flows with the map. also consider some elevation change to the floor so its not so flat then it changes the lines of sight.
Try adding some more objects to your map besides a few bridges connected together on the sides. Give multiple paths to each spot, make the map intricate(more or less) and give it some type of style or theme. Also, make it aesthetically pleasing while it still plays good. Adding just a few of those things could improve the map a lot.