I understand the issue you’re talking about. When mixing vocals I really keep folder tracks to a minimum so that I can still see as much as possible. If I’m mixing vocals, I’ll put all the lead vocals in one section and dubs/doubles in another area and I’ll route them to their own groups and the groups will sorta divide the sections, and sometimes I’ll color them to help differentiate them, but I won’t put them into folder tracks in order to save on space.
But it’s a somewhat small issue in my opinion. And I’m not sure this would be that great of a fix. At best you’d save a little on vertical space but you’d still lose horizontal space.
Have you checked out the visibility configurations? I think that’s really probably the better fix. It’s something I’m going to be trying to use more often myself. Perhaps they could also beef up the Zoom Preset/Configurations too so that you could save zoom presets that have certain folders open and closed and whatnot.