Sundance

Thanks for linking to your review! I'm sorry to hear Frederica doesn't come across any better in the movie than in the book. That's everyone's complaint about the book, too, that Lady Susan is the best character yet she's the villain. Frederica is an essential character but she has barely anything to say and mostly she's just described by other people.

In Emma Thompson's Sense and Sensibility, she greatly expanded the role of the younger sister, Margaret, who becomes essential to the storytelling in the movie rather than being barely there in the book. It's one of those things you can do in movies to illustrate things that are just narrative in the book. A movie version of Lady Susan was a perfect opportunity to improve Frederica's portrayal and benefit the story.

The reason Austen didn't try to publish this one is that it's too ribald for the product of a teenage English vicar's daughter, with the title character engaging openly in adultery with no significant punishment. Typical of the 1700s novels, but by the 1800s when Austen was publishing, people thought of novels as tending to immorality, therefore adult Austen steers clear of the innuendo and adult themes of Lady Susan. Adultery and scandal happen in her published works, but always in the background and always with calamitous results.

Lady Susan is not unpublished. It has been in print since the 1870s when is was published with J E Austen Leigh's memoir of Jane. You can get a copy of it fairly easily, usually with other minor works of JA's or her unfinished novels, The Watsons and Sanditon.
Frederica is supposed to be a bit of a sap. Lady susan isn't really like any of the heroines, she's like Mary crawford, isabella thorpe and Lucy steele rolled in to one which is fun

jules