I took the modly comments as an expression of frustration over a competition that stresses participation over quality

I think I would agree with that, too -- but it did make me wonder how much work on something is "enough," heh. But I'm getting a consensus from a lot of comments on this page that maybe a good rule of thumb is to feel that you're satisfied with your piece, or that you have learned from it or benefited from doing it even if not fully satisfied. I can work with that. :)

(And thanks so much for the kind and encouraging words. I do trust myself to write reasonably well-conceived fanfic on a good day, but original writing just feels like a whole different game!)