It would be best not to change what the buttons do very much. It could add unnecessary levels of confusion. "OK, I think I hit the wrong button, and now I'm not sure what mode the system is in... better look down at the controls while I drive along at 60 MPH."

Maybe I'm biased. My old car has a great UI. No touchscreen, just a panel of physical knobs and buttons for media and climate control. The phone integration could be better, but that would really just mean a place to put my phone (without clipping it onto a vent) and a stereo that lets me play/pause/skip songs on my phone using the car's physical media controls.