I agree, very interesting reading! I don’t have better ideas about how to introduce this kind of fairness at scale. Maybe it would be worth to “spec out” what GarageBand did (you are already doing most of this in your post) and post it here, only the list of features, to increase the chances that someone interested and with the developer skills picks it up? Could look like Overview of Bandcamp features (probably simpler).
About not getting feedback about the music you/we publish, I remember you bringing this up some time ago and I responding, but… I never followed up, and the problem starts with the difficulty of just noticing when someone publishes something new, even if the post is in our busy communication channels, somewhere. While the tech for a scalable system is missing, we could use the still unused Members > Our music space to review each other’s music.
I pledge to listen and comment on new and wip music posted on Members > Our music. 
And I encourage others to do the same. It takes only a handful of peer listeners to break the silence and maybe (just maybe) start a snowball effect.