Probably a whole other topic here, but another thing GVs should get is variable engine noise based on throttle position. It would be nice to be able to hear another vehical at idle verses when they are at full throttle on the move.
Your own engine noise should be reduced while at idle also. Disel is loud for sure, but at low idle you should be able to hear other things going on around you so you don't have to totally shut down the engine every time you want to check the surroundings.