I'm not interested in mundane AUs (or really any setting change AUs at all; I wouldn't be interested in reading, say, fic from a canon where half the characters are vampires and now they're all living in a spaceship or whatever). I understand the appeal on an intellectual level, but in general when I read fic, I'm reading it because I want more of the canon: more casefic like missing adventures from canon, more interactions between specific characters, more emotional intensity in specific character relationships, and so on. I want to spend more time in the world, and with the characters that I love, and fundamentally I don't feel I get that with setting change AUs.

The only circumstances in which I enjoy it are for canons that are fairytales, folktales, mythology, stories from religious texts and so on, because the details in those tend to be quite sparse (or the setting is just a kind of indeterminate fairytale land: a cold forest, an unfurling road, an isolated castle or whatever), so taking the story and transposing it to another setting doesn't feel like it's taking something away from the parts of canon that I wanted to see more of in fic.

In terms of a hierarchy/spectrum, I've honestly never really thought of things in that way. I just think of it as fanworks, some of which appeal to me and some of which don't.