The problem that Hyao has noted is that a lot of his dialogue presumes you're human, and going and changing all of that would take quite a bit of work.
This of course doesn't mean 'no never', but it certainly makes it less likely as it's a bit story important that you're a human when you interact with various people. Maybe 'for a single scene' sort of changes, I guess haha, but there is a lot on Hyao's plate now as it is.
But that's where preparation comes in handy... to suggest 'Only Human' up to this point is never immersive breaking. There are other alternatives, but yes... all in all everything assumes you're human as of now & the longer it stays that way, the less important & the more cumbersome this potential content becoems
There is still a lot of complexity involved to support other forms. You can template everything as "you stroke your [specie_adjective] cock", but that does not get you very far, and will "break" the story in many ways.
For instance, how would the villagers react if you keep showing up as different creatures every week? And a lot of the dialogue with Rhot relates to him reacting to your warm-bloodedness. How would he react if you had a different form, or if you change your form partially through your relationship?
And in order for the transformations to have any meaningful effect to sex scenes Hyao would need to add custom text for all sex scenes to describe how your tail is involved, how the characters react to your furry or scaly skin, and so on. So supporting transformations means that all current and future scenes will require considerably more writing.