> In my current run of the mill, screen based, "infotainment" system, doing this without endanger myself and others, requires stopping the vehicle, and undertaking a series of awkward and unresponsive controls, none of which are accessed on the same screen!

Toyota, the automaker under discussion here, offers steering wheel controls that are pretty decent. The main weakness of such systems is that the interface between stereo and phone has such little functionality, and that is where many people will be playing their music. Eventually you're going to be poking at a phone and a badly-designed app unless you're happy to simply play everything from a long playlist.