Eliminated units

[berto]

Are you aware that the numpad 0 key also toggles travel mode?

We are considering assignment of the currently unused 'decimal' key -- the key immediately to the right of the 0 key on the numeric keypad -- to the reachable hexes highlight.  That would again give you the two adjacent keys travel mode/reachable hexes combo you seek.  Not quite as convenient as the old T-Y combo (because a bit more of a rightward reach for the left hand), but good enough.

Note that you would still have the primary hot keys -- Ctrl+T, H -- for these purposes.  Also the toolbar icons (and menu selections) of course.