Hmm... I know all this and have read the entire series as you have (and see the film in an entirely different light, the books and the film series will be quite separate things for me), but what I'm saying has nothing to do with Rob being a 'sex symbol'. Maybe I wasn't making it too clear, but I'm referring to the media circus around Twilight and its sequels. The fact of the matter is that a great deal of the promotion from that film was spun on Rob's character. I don't just mean keep Rob in because he's attractive and will please his and Edward's fans - I don't think that the studio will miss out on potentially making even more money by having integrating him into the screenplay a little bit more than he features in the novel, but in no way changing the storyline as such, and including him heavily in New Moon's promotional campaign. The main aim of a film studio is to make money - where there's an opportunity, they'll grab it.