With the sounds already in BeamNG.drive, they are nice. But one sound that would be very interesting to be added to the game would be scraping sounds. These sounds could occur from the metal of the car sliding and grinding on the ground. ex. flipping the car over on the roof and sliding, or a car scraping on the ground by how low it is. I think this could greatly improve the crashing physics of sound.
Scratches have been suggested so many times but it has never been done because who knows why, This would be a good alternative though other than just sliding across the ground with no signs of damage or anything...
Scratches, scraping, sounds for everything you can think of, more cars, more maps, more optimization, and a slew of other things are planned and will eventually come to be. The devs know how cars crash and what sounds they make. Just hang on and be patient, it's all coming in good time. If it isn't coming, It probably wasn't ever feasible anyway, and anything related to sound is going to be pretty feasible. Try to keep in mind that this is not a finished game and every blatant and common sense flaw is not just something that was "left out" for no particular reason. There are lots of things that they just haven't gotten to yet.
I feel scrapping sounds should still be a pretty high priority especially for when racing gets added. It's pretty useful to know when your wheels fall off because you scrapped a wall.