Given how new the novel as a form was, I'm not sure if "reformed rake" was as recognizable a trope as it is now. There are early examples, yes, but not so many as to make it a genre. However, I totally agree that JA didn't like that storyline. But I don't think she changed her mind. The way I read it, what she is doing with MP is saying, "Yes, that's a romantic idea, but it doesn't work that way in real life. In real life, someone like Fanny will be happiest with someone like Edmund, and plausible charmers don't stick around."
