Yes, I agree with Tommy, more modulation domain <-> MIDI would be necessary. I like the "control/modulation" switch: that's a nice idea! Another way would be a global option: to ask all of the Control signals to be synchronized globally with the modulation.
One first modification I do to improve timing if I start a patch with a preset is to get rid of all graphic gizmos (example: moving sliders indicating rate of panning…).
The harmonizer has so many MIDI qualities (mapping, etc), I hope Eventide is listening.
