Yes, you may be right. I added the fake stones at 0.005m lately, but may reduce that to half the size and mask them by some pf. I think it needs more dirt and stuff too, but it's getting a rather busy file as it is already, so I have to choose carefully what to add (and how much time to continue spending on it).
You probably mean that the darker 'sand' is dirt. Well, I have to think about that too, should it be a darker (wet) sand or really dirt/soil plus the lighter sand. Don't know really, but maybe it's good to break the darker bits up to form more soily ground.