I know you're like "done" with this (shame I didnt catch it earlier)...but I think I'll make a comment geared to anyone making anything topdown.
I think it's important that the ground tile contains a lot of eye candy in it's pattern, while the walls are all about adding depth to the equation...and if posible those ground tiles one floor above the playing ground should NOT have the same texture as the ground, since they're not playable.
Here's two aproaches to it from Boktai.

an intricate easy to see pattern

and a grass based on a dominant flat color, with variation tiles toward the edges.
I feel like you're in the bad side of a compromise between these two aproaches.
http://www.mobygames.com/images/i/04/28/69878.jpeg http://www.mobygames.com/images/i/04/28/69878.jpeg these two are good examples of intricate patterns made to signify grass, from Animal Crossing....which has a kind of oldschool feel to it's aproach that seems relevant to your style