The Kanna san plot line is just so boring for me, I couldn't care less about it, feels like it's there just so the author don't have to write about the main "couple" which is not getting development at all since around chapter 60
Why would the author do that tho?
I just said it? Because the author doesn't know how to develop the main couple, it hasn't developed at all since Aya discovered Koga was "oni-san"
I mean, this could be just due to perspective, but I can't really see a reason to agree with this. Progress has been made, even if a confession hasn't happened yet.
Also, to me at least, it feels like the situation with Kanna is not only to act like padding (since a story resolving too quickly can technically be a problem), but to also give a proper identity to the Uncle, so he's not just someone who simply exists.