[FernetMenta]

In my opinion there are conflicting interests; an add-on would be the easiest and non-main-branch-intruding way of implementing the control channel but doing it in an add-on (you cannot come 'higher' in the architecture...) is what you are opposing

I am not opposed to doing this in an addon, I just don't want the addon to be hooked into the sink. In case such an addon becomes activated, set volume of AE to max and direct volume control to the addon. That would also work for passthrough audio.