was unaware of this thread, which (at least in part) contains my request. my own is posted here: https://forum.renoise.com/t/minimize-tracks/30927. it concerns the ability to minimize/hide tracks in mixer view particularly. however, this thread has a lot more good ideas to improve the way tracks are handled in Renoise, and this is the thread that should be followed instead of mine.
+1 for all of this here.