With a better UI people could really do anything - very little in MB requires 'skill', it's basically data entry, but the lack of any kind of 'learn by doing' tutorial or similar just makes it a very steep learning curve.
On a more positive note, this kind of thing could be what you're looking for re. steering people towards easy things they could be doing:
Any kind of system where someone can be rewarded for doing a specific thing (eg adding cover art can be pretty basic, or applying guess case to certain releases) would be super useful. Otherwise even something like a weekly/monthly 'focus' where everyone is encouraged to try work on one element of the database would be cool.
Anyway, really agree with you, for me it's a 100% UI issue at the moment