that is very very good my friend, it really is rare to see an isometric trying to be realistic, last one I remember was Mahjqa's little train thing...and that was ages ago.
Your piece is also good because you dont attempt to detail everything, you do have some specific detail here and there, but most of it is texturing which's what's appropiate for that scale, very good.
Main crit...your water, you know it has that pool blue to it, makes it look all fake and takes a lot away from the piece, laguna type things usually have a more murky look, they're more like a blueish green towards a very greenish brown.
Most of it...but specially the most abundant grass seems a bit too saturated too, you might want to tweak the grass hues to be less full-on green and be a bit yellowish, and you should also down the general saturation a bit.
SPELLCHECK!
