A good outside dump is undoubtedly one of life's great pleasures (who want's to squat on a smelly "bucket" in a vehicle when you could be out in the fresh air with a nice view?) Sadly, like many other things in life, if too many people are doing it (and doing it badly) it becomes unsustainable and a rethink is required.
Anyway, there is no excuse for not doing it properly. Look for a spot where it is very unlikely other people will go at all, cover it, and don't use bog paper (which is often the most offensive thing) - a handful of grass or whatever, even a stone, work perfectly well.
The plague of camper vans overrunning the country does seem to be an out of control problem which I really do think threatens our experience of the outdoors. Their visual impact in every layby is probably just the tip of the turd.