I am +1 this feature suggestion i.e. making the midi implementation more complete so I can add either off-the-shelf midi controllers or build something from scratch that will give me more hands-on control over the SQ functions.
My use case is music production with many hardware synths, samplers and drum machines. I monitor the hardware live, and multitrack either to DAW or USB SSD on the SQ, but do not always use the DAW for playback and mixing, so the monitor control features suggested by Phil in the original post would be most useful for me to access from a custom midi controller for when I’m not using my DAW (which has those features available and are easily mapped to midi controllers).
I did find the document linked below that gives us the NRPN data for what is possible to control:
https://www.allen-heath.com/media/SQ-MIDI-Protocol-Issue4.pdf
Massive thanks to A&H for making such a great console – it does a great job for my use case, and now I’ve got the NRPN data I can build my controller mappings for most of the things I want (levels, mutes, sends etc) but the monitor controller features would be super useful to map also.
