I got a car whose cruise control state was never displayed (the mechanic used the wrong dashboard), but since it worked anyway, I accepted it. So that's a data point (me) that modal buttons do work.
But "should not depend in the GUI to keep up" is wrong, I think. It needs at least one LED per mode. Because sometimes it's a bit annoying. Rarely cruise control doesn't engage or turns off by itself or something caused the cruise control mode diverge from what I have in mind, and a quick glance would help to resync.
I am not ruling out the GUI. I just should not be required to look at it. The GUI is a necessity for learning, but once you know a key sequence there must not be a delay before the second click can be made.
The menus should be shown on the dashboard (not on the central screen). I would argue that that would be even safer than trying to look at the symbols in the wheel/stalks while driving.
But "should not depend in the GUI to keep up" is wrong, I think. It needs at least one LED per mode. Because sometimes it's a bit annoying. Rarely cruise control doesn't engage or turns off by itself or something caused the cruise control mode diverge from what I have in mind, and a quick glance would help to resync.