Continuing the discussion from Speaker Processing Mute per band:
I think this would be extremely useful, but in addition I would suggest there be output mutes which would give even finer control, particularly for troubleshooting specific destinations such as speakers rather than just crossover ranges.
To facilitate efficient testing, creating something such as mute sequence groups where you would be able to test all speakers in an array by output or zone to unmute in a sequence based upon a specific unmute time constant. You could then step through each output assigned in the group to ensure signal is being output. Using the SigGen as the input source.