Sustain pedal support.
Edit (after Icoustik's feedback I have made this more specific)
1 - If we could learn commands (play, launch/mute etc) to an incoming CC command we could start and stop a song, or launch a part, using just a simple sustain pedal.
I've found that midi pedals (especially 5 pin midi ones) aren't that common, and can be expensive - a sustain pedal on a keyboard is the cheapest, most common way of sending a midi message to the deluge with your foot and leaving your hands free to play keyboard or guitar.
2 - a simple on/off sustain pedal is currently unable to be patched to the 'release' parameters in such a way that they jump to 50 and hold a note the way you would expect when a sustain pedal is connected to a keyboard.
Is it conceivably possible to receive incoming CC messages in future? I think this would be really great -
1 - It would mean you could use a sustain pedal with an external keyboard to make notes longer in the normal way
2 - If you could use a CC message as a 'learn' command, you could stop/start a song or part by hitting the sustain pedal.