It seems nobody remembers the reason for the F-key assignment in the original i.e. Norton Commander... The assignment was very logical and easy to remember (and use) on the original PC keyboard, where F-keys were located in two columns on the left edge of the keyboard: F1, F2, then F3, F4, and so on. You can immediately see the advantages of the F9 location (the leftmost key at the bottom) and of the proximity of the Browse and Edit keys. I used my left thumb to press F10 - it was in the correct place almost without palm movement...

Nowadays I almost don't use Mc (except for file manipulation) because the Linux version has a serious weak point - it blocks the most important keystroke in shell: Tab. It is of course traditionally reserved for panel switching but this role could be deactivated when instead a single command line zone MC would allow to have a multi-line (in NC it was 3 or 4 line) zone for the shell scrolled display. This way it would be possible to have the full-size panel display (with the Tab switching panes) and one keystroke away reduced-size panels with full functionality of the shell tab key in the alternative panel mode... Another disadvantage is the complicated way of changing settings (especially the colors and file attributes display format) in practice forcing trial and error mode... True, it's not needed often but spending hours on it is rather deterrent.