I, too, would like some clean-up in the BB editor if it's possible.
I really like the idea of hiding unused tracks if that's an easier workaround. So +1 from me.
A thought I had was that maybe there could be a BB Editor (the existing one) and a Loop Editor, which would act like the existing editor except when you create a new one in the Song Editor, it does not have any instruments from previous loops.
Maybe I'm already asking for the same thing as suggested above, which would make it too complex. I don't have extensive programming experience, but wouldn't creating a new loop ( named, say loop[1] ) object allow you to have completely separate instruments from the previous ( loop[0] ) object? I suppose the difficulty would be integrating that into the actual song itself. I don't know. Again, not much programming experience.
Anyway, from an artist's perspective, having a blank, clean loop editor would be lovely.
Thanks, devs, for all you do. I LOVE LMMS.