Interesting start. I seem to think that there may be too much land there. What do you expect the rise in water level to have been? Can Fractal Terrains take the current map and drop the water by 10, 20, etc feet.

hmmmm quick google and a best guess is that if Antarctica melted totally, the sea would rise 61 meters(200 feet). So.... depending on how much ice there was compared to earth, 100 feet might be a good value to check.