Midi out would be amazing! Exporting is great but 3 channels out to control various synths and drum machines could be endless inspiration for continued practice. With this Ableton Link would be an almost necessary addition.
Another implementation I imagine is each chord symbol in an arrangement as a button that triggers chord as midi as well. Allowing different improvisational arrangements of chords that already work together, sent to favorite sound source. Of course then Audiobus and AUM compatibility would certainly be just the bees knees as well.