Maybe a boondock/dry camping section where you could input a dry campsite based on your GPS coordinates and write a description or upload a picture. Amenities would include level parking, fire ring, clean public bushes, etc.. This would give us a chance to share/find those spots that aren't on any map. OTOH, it's kinda like giving up your favorite secret fishing hole.
I don't think an app would make it on this alone.