In addition to some of those problems, the individual leaves on the trees don't pop very much, making the tree canopy itself, look very flat and smooshed.
The grass itself, looks lovely, and I don't really think you should touch it! Instead, take a note from SD3, and add a separate layer of tile-able tall grass.
The path does look very nice, I like the colors, but I feel just a wee bit more contrast could be used to establish the darker areas/cracks in the path from the lighter areas.