I have been using the iOS app almost daily for a few years now. It is brilliant: indispensable. It was before Re-Frame, and that feature is astonishing.
I would very much like to be able to MIDI control the Re-Frame percentage (fade the backing in and out) using MIDI - my goal is to be able to stay on the waveform & markers/loops view whilst using MIDI controller hardware to adjust the amount of Re-Frame isolation. But it seems that parameter is not as yet MIDI controllable (I guess the MIDI implementation predated Re-Frame).
At present, unless I've missed some clever shortcut, I have to tap screen to the Re-Frame page, adjust from, say, 100% to 80% isolation with the scroll fader, then tap the waveform button. For an occasional adjustment that’s no hardship, but it’s one I perform constantly so starts to become frustrating!
I have no conception of how much/little work it would be to implement, but it would be fantastic for my workflow (transcription for personal use) to be able to MIDI that Re-Frame parameter (other Re-Flow parameters could be useful too, but that single tweak would be uniquely useful!)