The thing about fandoms and fanworks is that a lot of the time, my desire for fanworks is driven by flaws in the canons themselves.

I think I see what you mean. I wouldn't say flaws, in some cases, but "open questions." I read some articles by Suzanne Scott about how creators can stifle fan work by interpreting their own text for fans and pre-emptively declaring the truth behind ambiguities in the text to fans, shutting down alternative interpretations and creative gap-filling.

One of the articles is "Authorized Resistance: Is Fan Production Frakked?", but I know she's written about it elsewhere.