Extend a cable & reset button for firmware flashing to the outside of the enclosure.

Make it show ETA based on percent completed.  

Show the filename currently being printed.

Make "stop printer" the last item on the menu instead of the 2nd to last.  

Make highlighted item inverted instead of an outline.  

Make navigation faster.

Fix bug where it sometimes highlights the wrong item.

Sort files by date.

Helas, the physical interface should have a joystick in addition to the encoder.  Imagine moving the print head with the joystick & the Z axis with the encoder.  A joystick button would be the select button for gcode scripts & the encoder button would be for navigating menus.