I'm not expecting a simulation of Spintires that destroys CPUs. But something so that dirt isn't just solid concrete with less traction. Especially since BeamNG's main setting seems to be more nature-based.
If you load Grid map and drive around, you can see there is test areas where is mud, water, ice, grass and sand, if you drive on sand, it will be deeper on one end and less deep on another. Try different cars there and you can see how sand is not necessarily just flat concrete like. Also with latest update they have made mud and sand much more realistic, it is not just question if map makers start to use these new features, so that you sink in if you get stuck in sand if you drive out from the road with tires and vehicle that should not be able to do so. It is new area so not much maps use these possibilities, but hopefully in future going out from black stuff has realistic consequences.
Do you prefer what you see or do you prefer what is really? For me it is implemented already, you just can't see the effect like in spintires: https://www.beamng.com/threads/my-idea-of-more-realistic-snow-for-a-map.38731/#post-582654