Here's the thing though.
Look at what kind of Book to Film adaptations were happening before LOTR, and Harry Potter were running the show.
There were plenty of great adaptations before LOTR and HP (Gone with the Wind, To Kill a Mocking Bird, Godfather, to name a few).
Look at the kind of concessions the Jane Austen Society have made regarding her books.
Pretty much everything I've seen is fairly close to the books (with movies having to cut more stuff out, of course).
In comparison to the way things used to go (I feel the trend is coming round to the more faithful adaptations after recent successes. Marketers like making money after all.) these adaptations are quite faithful.
Perhaps I should say "not very faithful" or not as faithful as they could have been.
I understand this might seem like your spouse saying that they only watched porn, rather than hiring enough hookers to get every STD known to man, so they were being really faithful.
Jackson said from the outset he wouldnt be able to please everybody. That scenes and characters would have to be cut, or their roll reduced or altered. I get that. Books dont pace themselves the way movies do, the timing and exposition is like night and day.
Look, no one expects a literal adaptation - it's not possible, even with the TV shows (although I wouldn't mind seeing miniseries with a season per book). I also realize there're certain things the general public expects from Hollywood blockbusters like action and battle scenes. That's all understandable and I love spectacle too. What baffles me is when PJ removes great scenes from the book and adds stuff that makes no sense. The Osgiliath scenes in TTT is a prime example. The scenes in the book were perfectly tense on their own, instead we get character assassination of Faramir and unbelievable moments with Nazgul. What's ironic, the scenes likely require more screentime than a more straightforward adaptation of the book would have. There're other moments like that, when Frodo believes Gollum over Sam and Sam decides to leave, Gandalf basically pushes Denethor into the fire, Gandalf loses to the Witch-king, Aragorn beheading the Mouth of Sauron, Ents being tricked into attacking Isengard, etc. I can't call any adaptation faithful if the characters act in a manner totally opposite of their nature. This is not simplification for the visual media, it's a pure travesty. Are viewers really so stupid they wouldn't appreciate more subtle drama or heroes actually being noble for a change? I think it's PJ who simply can't do movies without over the top melodrama and overlong action scenes.
I suppose it could have been worse... but it could have been so much better - with more proficient writers and less self-indulgent director.