The ability to add Continuous Controller MIDI Effects (i.e. a knob with assignable CC send and receive numbers) would allow for:
- easy sending of CC data to external instruments
- remapping of CC data (by setting send and receive to different CC numbers)
- creation of reusable MIDI Effect Racks for control of external / hardware MIDI instruments.
It is the last item that I think would have the most value. For example, a user with a hypothetical external "InsertSynthName" could create an "InsertSynthName Filter Rack" with a number of Continuous Controller MIDI Effects assigned to things like filter cutoff, filter q, filter resonance, FLFO amount, FLFO speed, etc., and then assign Macro knobs to one or more of the Continuous Controller MIDI effect values.
The resulting racks would be simple encapsulated editors for external instruments controllable via clip envelopes, the mouse or attached controllers -- all without having to remember CC numbers.
Combined, such racks could act as simple editor/librarian utilities for hardware instruments. And of course once a user created such a rack they could reuse it via their library, or even share it, adding value for anyone with an "InsertSynthName" in their rig.