1. Default presets. When you enter the car, you press a menu option to immediately set the car to all your settings (radio to the right station, GPS app opens,seat moves, etc.) (could be done with a button too honestly
2. Increased primary element size - Use 90% of the screen to display the setting you are changing so you don't have to look directly at it. Reduce the size of options you are not currently interested in changing.
3. Gestures - Use gestures to change settings using your muscle memory, not eyes.
4. Use the iPad to display video that helps you drive (blind spot, backup camera)
5. Use of color - When you crank the heat the screen is cast to in a red shade. Make it more intuitive at the subconscious level.
6. Full use of screen to make a change - When you want to adjust with a button or knob, you have to get your hand exactly on that button or knob. But on a screen, you could swipe left anywhere and get the same effect. This would use significantly less attention.
7. Contextual UI - The car notices the windows are fogging up and prompts if you want to turn on screen defrosters.
8.Multiple UIs and UI customizability. Don't like this UI? Try this one! Or just change the one little setting that annoys you. It's your damn car.
9. Stopped? Here's something interesting put on the screen so you stay engaged.
10. Safety tips (stats on your driving, or suggestions on ways to drive safer)
11. Haptic feedback - When you make a change, the screen could vibrate to indicate the change was received
12. Shortcuts - Have your favorite driving settings most conveniently available
13. There's probably more, but if I wrote a 13th one, it would be unlucky! :P