Hmm, looks like you have some combined some incongruous styles here. The dark black stroke surrounding the land would have been more appropriate to an atlas style map (though even there I would have lowered the opacity a bit), but it doesn't really work with a semi-realistic/artistic map like this. You might try changing the color to a tan/brown and lowering the opacity, but honestly I'd probably just get rid of it altogether myself. The mountain look pretty good and the forests are ok but the rest of the land looks a bit too blue which, were the black borderline not there, would make it nearly indistinguishable from the sea. You might want to add more browns, tans and greens to the land to help distinguish it from the sea.

Cheers,
-Arsheesh