Pratfalls and Problems of the Page to Screen Transition

Disclaimer: If you aren't a fan of the Harry Potter series of books/movies, chances are you won't get anything in this. You've been warned.
 Here's the trailer for the new Harry Potter movie.
 I'm cautiously optimistic. The past few years when I've seen a trailer for a Harry Potter movie, I've been all psyched and can't wait to see the movie. Then I see it and it's like 'meh'. From films four to six there have been so many crucial details left out that it has been infurating. I was really spoiled with the care and reverance that Peter Jackson and his crew put into the Lord of the Rings films. Yes they differed from the books in a few ways but any true fan knew that it would be impossible to completely take the text from the page and put it up on the screen.
 It's different with the Harry Potter films for me though. Because they have changed so much from the books that some parts are irrecognizable. The last 100 pages of book five, for instance, feature some of the best written, intense action set pieces I have ever read. When you see the sequence play out on film it's WTF-inducing. "Why aren't they dueling? That's not dueling. They're just like flying around. They can't do that."
 Book four, The Goblet of Fire, was a major shift for the series. It takes the main characters into seriously mature territory and someone actually dies, something that would become a hallmark of the series from that point on. The book weighs in at over 700 pages...so of course some parts would end up on the cutting room floor. Two important characters and one whole storyline (Hermione and Dobby and the House Elf Liberation Movement) get completely scrapped.

 The slicing and dicing is fine I guess considering that most of the people going to see these films in the theatre have the attention span of a squirrel. But what about the die-hard fans? Why not take a page out of the Lord of the Rings playbook and release a set of extended editions DVDs/BluRays. The Order of the Phoenix (the longest in the series) is 860+ pages! The Half Blood Prince is over 600. Each of these books is filled with a treasure trove of detail and complex characters with their own stories. Fans who opted not to read the books have missed out on a LOT. Finally, with one last book left to adapt to the screen with its own set of intricacies, the producers decided to make the film in two parts. Hopefully this move will present the story in the way JK Rowling intended it.

Here's an old LOTR trailer. This is a great example of how to take a beloved series from page to screen.