At first I thought I would use the sketch button, but after a few unreadable try in bumpy condition I went back to the kneeboard, but it is not hard to get to setup so I learned to live without the setup button.
Ciao
To take it even further than what Doug suggested: It might be neat to long press any of the buttons to open a menu that allows you to select what button you'd like in that location. I never use the North Up/Track Up button for instance.
I don't know that I would change the buttons from the default, but if a person would like to then I like that last suggestion (long-press to configure buttons). I think it fits in well with the overall UI and the similar configurability of the instruments.
I sure hope this idea of making the buttons configurable gets some traction. I really want to get the Setup button back on the main screen as I use it quite frequently, and don't use the Sketch button at all.