Those are some nice design elements for the map. I can't wait to see how they play out in execution. My one thought, with no idea what you are going to do, is that the vivid colors contrast in my mind with an underwater scene. Although its certainly accurate once you take the water out of the equation, the map might be more evocative to a surface-dweller if you washed over everything with a murky blue and dulled down some of the colors.