the ability to view multiple different instruments in separate track groups

[Lopyt]

I think its fine as it is, and I don't believe OS is very intuitive at all, especially not with all these hidden menus and keyboard shortcuts. What would be a better thing to add I believe is a completely new UI for markers, and perhaps a better implimentation of the instrument panel that displays more than just volume slider, for quick access to instrument settings. A horizontal only zoom may also be nice if it can be added in a way that doesn't lag the entire sequencer.

To access only onle instrument notes at a time by the way, try pressing ctrl+the lock button next to an instrument on that panel thing