Do that island a favor and put some more rocks and maybe some snails on it :) And maybe you can find a different texture for the shoreline?
Ex: from light a little bit darker around the water: http://geoffhale.com.au/images/Tropi...Island%20A.jpg
The mainland is not far, peasants can swim across watter to mainland :D
And about terrain... I do not see nothing special on it... No doodats (almost), no fog... Nothing... You should renovate it...