I gotta say, that sure does look nice!
The connecting tiles such as paths and tall grass look nice, and make it easy since it's automatic.
I noticed that the trees' and rocks' (entities?) shadows overlapped the tall grass and water.
I'm guessing you put the tiles into one layer, and entities on a higher layer. And since the tiles are drawn first, entities then will then overlap tiles.
Is the water animated? What about the tall grass when you walk over it? The reason why Nintendo doesn't connect the tall grasses is probably because when you walk over it, the grass shakes (2-3 frames). Animating each piece of grass is hard, so they leave each one individual. I don't know if it's like that in the newer Pokemon games, since I don't play them, but it would look nice if the water and tall grass are animated.
This kinda motivates me to get back to Xna. Nice work! [I rarely comment]