I'd like to see deforming mud, dirt, grass when driving offroad. Also perhaps have the mud and dirt build up on the vehicle also. Example mud runner.
Where as I do agree immensely, I would think this would be too intensive graphically. Large game slowdowns
This has been discussed before. It is not advisable to create a thread for something that's been explained already unless you have something new to add to the discussion. Deforming terrain would essentially require a jbeamed map with multiple layers. Which is recource intensive. Maybe on smaller maps/maps with not much off road, but it wouldn't make sense for some maps to get this and not others. As for dirt and scratches, I remember at least one mod maker experimented with this. It would require multiple UV layers to do properly, which would get annoying fast to implement. Doing this with some shortcuts is difficult to get right; it can get visually ugly fast if shortcuts are taken with something like this. Something would be better than nothing though IMO.
I doubt the map would be jbeamed. It wouldn't need advanced softbody physics to deform. It would likely use a similar system to Spintires (although I don't know how it works)
To my knowledge, Spintires/MR system is only as good as it is because of features specific to the HAVOK engine. Any decent form of ground deformation will require a lot of extra information. Contact points of the car, ground preasure, type of ground, etc... However that would all mapped in BeamNG, I can't imagine it would be easy on performance.