although I still have no idea what the command bus might be or offer…
I was working on a patch earlier and was thinking, it would pretty slick if you could i.e.: “tag” a parameter from any unit inside the custom unit, and this would create an ‘alias control’ that would show up on the custom unit’s surface layer (as well as the control list so you could re-order). The fader or button would behave and update exactly like the real control it’s aliased from.
The chain routing on the subscreen would be of the actual subchain of the control it’s aliased to.
I’d never want to abandon the local controls, but think in some cases this could eliminate some extra in between routing if you wanted to control a single specific parameter on the surface that’s deep within the custom unit.