I know enough about movie making to know that what works well on paper isn’t always feasible in the movie and movie-makers have to keep that in mind when creating their products.
For example, when X-men came out, fan-boys were waiting to see Wolverine in his yellow costume and were highly pissed when Bryan Singer didn’t have that. Singer said that they tried a yellow mock-up to see how it looked and the colour looked terrible on film, so they chose to go with film reality and dropped Wolverine’s yellow costume.
Peter Jackson wanted as close to the LOTR as could be done on film, without taking undue risk of creating confusion or unworkable situations. He even fought the studios, which wanted a five minute overview of the previous films just so he could have that extra five minutes to cover more material.
You have to keep in mind that Peter Jackson and the studios were risking 800 million dollars to make the film and have the possibility that the subject material would be something studio audiences couldn’t relate to.
Jackson is brilliant in his portrayal to the movie. It’s no joke that he tried his hardest to stay as true to the books as possible... The movies - for their genre - are masterpieces just as the books are to epic literature.
He made multiple changes that are not explained by the necessary transfer from book to film.
For instance, changing the motivations and personalities of major characters, changing plot points, and making the personalities/motivations of certain characters so similar that it was difficult, at times, for those who had not read the book to differentiate between them.