Wow, this is pretty awesome!
I think I'll try it today
By the way, Opening up the image in Photoshop and applying a Smart Blur (2[or maybe 3?] pixels, 45 threshold, high quality, normal mode) smooths most (though not all) of the more troublesome over-pixelated areas, with only mild damage to the image (swamp bushes of a specific kind got blurred). It keeps mountains/castles and the like the same way they were before, but makes most of the terrain easier on the eye.
Also, Edi, 666 Posts
EDIT: Forgot to mention you should first copy-paste all your white pixels to a new layer, then do the blurring, then make sure no new white pixels were added, then past the white pixels back.