Would be nice to be able to send stomp on / off and CC data on to additional outboard devices.
Suspect MIDI might do this for MIDI enabled units, but for instance I'd like to try using one expression pedal on both the Kemper and the Line6 M13 - perhaps both wah settings.
This could help simplify my life when the expression pedal isn't used for one or the other... and give some creative craziness when used to do two different things at once.
Bonus if you can set an invert function (toe = treble on one, bass on the other.)
This might be something to think about for the official companion footboard when that comes out...