The steering wheel is where most of this stuff should be all the time. The second you force me to reposition my hand, security levels drop off a cliff, since you get involuntary movement on the other side (as proven by this post) and likely take your eyes off the road, which is bad even for a split second. I know this for a fact, having crashed a car on a motorway as I was turning down the fan (controlled by an analog button, btw).

The best car interface, imho, is something like a rotary device or arrows buttons on the steering wheel (or back thereof) which can be used to manipulate an overlay projected on (or just below) the windshield. My current VW gets close, but the screen is in the lower half of the dashboard (way too far from actual view of the road), and the system can only be partially controlled by on-wheel buttons (the main control is a touchscreen in the middle of the car).