To implement what we all want and need should not need a “redesign”.
Just keep the “mixer-sidebar” controlroom as it is at the moment (please do not change again and again) but just add something like that “Cue-Mixer” - GUI could be based on the Mixer GUI - but just with “controlroom / Studio channels”.
If those Studio Outs / Cue Sends could be “part” of the Mixer itself we could just set up one of the 4 mixers for that - disabling all other channel-types… only keeping the Studio Outs 1-4 - or better - 1-8… Ok - there needs to be integrated all those metronome options though… but after all; This would be all we need I would say.