7. Allow boxes to be "immune" to clicks so that view-only sources are not accidentally put on air.
8. Tally lights! Boxes could get a red frame, or colored icons in assignable positions. Professional equipment usually has a red tally for "On Air", green tally for "On Preview" and a yellow tally for other purposes like "On Secondary Output". Ideally, I would make the colors assignable to various states or none. Why be bothered with any tallies that you are not concerned with. As for that secondary output? It's massively important in bigger shows and it'll only be a short matter of time before OBS users are asking for it. I already am.
As for having a VU meter, waveform monitor, vectorscope, etc show up, I would make those as filters that take audio or video input from a source in a scene and produce a video output of that instrument as that scene. Although I would not have any issue with VU meter overlays on the multiview itself either. Having a way to put Preview in a scene as a source would then make this approach really useful (unless it can already be done and I missed it).
This sounds like a big list but it's all simple stuff. It's what we've come to expect from production switchers for many years now and there's no reason not to run the full 100 yards on this one.