Kennedy>Hannah so I'm fine with the shift in discussion.
Until we get more with Kennedy, they are a fetish character. I get the defensiveness, no one likes seeing a character they developed degraded like that, since you want them to be able to stand on their own and not be "anal girl" or "angry stripper."
The problem, like Mav mentioned, is that it's done this way 90% of the time. Until proven otherwise, we as readers can either have blind faith, or assumptions this is just going to be like a trans character in any other VN. It's on the writer to deliver.
As far as Kennedy's popularity, I'd argue it's specifically the fact we've interacted so little. They are attractive, our interactions have been pleasant and there's a degree of mystery to it, leaving people wanting to know more about them. I compare it to how Tommy was handled in the first season of Power Rangers. Comes in with a huge arc, and then isn't on every episode so that kids would tune in everyday looking for him. The only thing Kennedy is missing is that huge initial arc.