I think you should add something to the water to indicate it's water, maybe waves or something like that.. because the land-water effect can pretty much go either way at the moment, gradient inversed or not. What I noticed about the coastlines.. that the roughness difference is huge compared to the symbols used here. It might be a closeup from the original map, but this might be something to work on at some point of the map creation process. Other than that I think it's coming together very nicely.