I’ve come to the conclusion that if you’re doing any kind of httyd AU, the dragons kind of…can’t be human? not unless you want to change up their relationship with the “vikings”. I mean, it’s not as though the dragons in canon are exactly…subservient, but at the same time there’s this feeling of “and now everyone has one!” that wouldn’t sit well with me were they, you know, human people.
so the conclusion would have to be just a simple “and now we’re all friends” instead of “and now we have augmented our society with the powers of these former enemies!!” also, the whole “we’ve killed thousands of them” thing would be a lot harder to just gloss over.