There is a plot line in the book where Lucy Mancini, who only appears briefly in the movie, falls in love with Sonny because he is a large man and Mancini is very loose down there. Then she meets a plastic surgeon who tightens things up down there and she is much happier and lives happily ever after with the plastic surgeon. That is really a plot line in the book. Even in 1969, people had to be wondering "WTF is Puzo thinking with this?".
Every woman in the book is either a nope or a Madonna, and other than Kay, they are all idiots. Even Kay is not all that bright.
Connie is a whiny brat in the book and the first two movies. I actually like III, in part because the female characters are so much more interesting. Connie goes full blown gangster in III, ordering a key hit without Michael's permission, and then performing another hit herself.