If a person that is writing a manga's opinion is that a relationship between a teacher and a student is harmful to the student because of the age or the power dynamic between the two, fine. But don't take 10 volumes to figure out that the love story you are trying to write is deviant. That kind of story is fine, but do it from the beginning so that there isn't a change in tone which makes it seem like the author doesn't know how the fuck he was going to end it.