I disagree with the fact to view ONLY original scores, but I love the idea.
Solutions I believe would be either: Brendan B's idea to allow people [guests] to tag themselves the songs they're listening to. If a hundred people tag a song as transcription/arrangement, well it would mean it is.
Either: Allow negative ratings. It doesn't resolve the problem that much, cause it would bring another lot of problems, as someone can dislike a self-composed song, but it is still a better idea to let people evaluate content.
Not even a feature page. Redesigning the home page to make it like YouTube (not the same, but the concept would be the same with featured scores instead of videos). It would bring a lot more views to top-quality scores that deserve some.
Well, it adds itself. I rarely have to add measures in the middle of already built ones.
Crescendo features that would be interesting:
Instead of basic folders, we could organize our songs [scores] into albums that would have cover pictures.
Those pictures would maybe attract (or not) more people. If someone doesn't upload it, it is probably less quality.
It could be a good fix to the "Show if a score is orignial or not" issue. We could determine ourselves its quality.
More, there could be a "By albums" option in the public scores section.