It seems to me that there is room for improvement of grass runways, taxiways, and aprons.
First, the grass could be a bit darker and less "bland", which would make it fit in better with the FS textures. A grass apron stands out way too much right now.
Second, the runways have "wheel markings" and the taxiways need these too, perhaps to a lesser extent.
Third, I am not sure what the thinking was when the runways were made semi-transparent; was there supposed to be a grass apron underneath them? Or were they supposed to allow the underlying FS texture to show through? Whichever it was surely the same should be true for the taxiways too, so I don't see why they were made differently. Either make both semi-transparent, or both opaque.
I find myself making more grass fields than any other type, so I would really like to see this happen.