My two cents as a newbie going through this thread.
I sense a current that assumes that the quality of a potential contributor could or should be measured by his/her ability to learn and understand a (possibly) not-to-easy to understand and learn user-interface.
I would argue the opposite.
You might chase away potential very valuable contributors with valuable knowledge and understanding of music/artists/genres/labels etc., because they are not particularly seasoned, savvy, or interested in spending much time and effort in learning a sub-par user interface first.
Or, the opposite, a computer savvy person who understands the interface fast, might be mediocre in the quality and/or value of his contributions.
In my opinion you should separate the underlying challenges, and strive to improve each of those specifically.
A sub-par interface? Try to improve that.
Sub-par and problematic contributions? Try to improve that. (by e.g. training/monitoring, and possibly a warning/ban system.
But in my opinion trying to solve possible problems at 'location B' shouldn't be addressed by refraining from making improvements on, or fixing issues at 'location A'.