“Many of those using “fanfiction” as a disparaging label appeared to be people who regularly read, write, and enjoy fic — a curious, self-effacing thing I’ve seen a fair bit over the years, fans’ way of diminishing their own writing in the face of creators’ “real” work.”

I find this endlessly fascinating. There is a lot of terrible “plot driven” writing out there that is a poor facsimile of something that came before it. I don’t think the source (produced by a fan vs. a “traditional” writer) should play much of a role in how it’s judged. I understand your point about self-disparagement being a defensive posture, but I hope more fanfic writers begin to hold themselves and the work they produce to the same standard they hold other work. I don’t really care very much who wrote a story or why; what matters is if it’s good or not.

The canon vs. fan speculation divide will always remain, though. Work that is produced or sanctioned by the creators can’t really be considered fanfiction even if the label fits in every other way.