Well, this is the first direction I am hesitant about. I don't see the upside in making Miki have romantic feelings for her sister, but we'll see? Couldn't she have had conflicting feelings for literally anyone else? Hopefully, it's at least handled well.
Still, I am not sure why mangaka go in this direction so often. Is it just that it's become a trope we insert at will out of habit? I know it's often represented as a "cute," confused phase that she'll likely move on from (and obviously Aki will never take this seriously) but still, it feels overrepresented in manga.