I disagree, these are adaptations of the books, and they are told from Harry's POV, it is Harry's story, therefore he should be in practically every scene. This particular story is about his internal struggle after the events of the fourth book and therefore that should be the focus, it's a very emotional book and while they will have to cut down some of his angst, they will have to keep much of it in otherwise they'll have completely missed the point of the book. This will be the hardest book to make a good movie as it's very long, and they'll have to find a balance between his journey (which is the most important thing) and action which audiences love. I hope they do it well but i'm worried!! It could make an excellent movie, but it could also make a terrible one.
Also I know quite a few people dislike the book, but I recommend anyone who's only read it once to give it another go, the first time i read it i disliked it, but i read it again and took more time over it and, while i agree it's overlong, now it's my favourite of the series.
Rita is going to be and should absolutely be cut, they can easily do the Quibbler interview without her. The film is already too cluttered methinks.