DROOL!
I like the water texture, myself ... it looks like marble instead of water, but I like it. You might want to make it look a little less smooth, though, maybe a photoshop "render lighting" or something to bring the variations up as a texture. Maybe you should apply some perspective, also, so the top of the texture is scaled down compared to the bottom, you know, to make it slant like the rest of the map.
But I definitely think you need some kind of shading at the coasts. The land/water transition is too harsh.
That's really beautiful work, man. Cheers in keeping it monochromish, too. I like subdued palettes.
So you write, too? Where do you publish?