For pity's sake, I don't think that Peter, Fran, and Phillipa have gone to all of the trouble of braving fanboy ridicule by beefing up the Aragorn/Arwen love story just to ship her off to Valinor. He's trying to build a little dramatic tension. Ever hear of it? It's that thing that you have as long as you want in a 1300 page novel to build, but that you have to do in a concise way in a 9 hour movie.
If you watch the director's commentary on the extended edition, Peter et al. say that they hope that most fans will get to watch the extended edition before TTT comes out because of the extended gift-giving scene. But then they point out that the casual movie-goer is probably not going to notice the continuity problem, since unless it is pointed out to you, there is no reason to think that there is anything special about the daggers except that Merry and Pippin had them. Since my wife (who hasn't watched the extended edition yet) didn't notice when we saw TTT, I think they are probably correct in their assumption.
(BTW, if you haven't listened to the commentaries on the extended edition, do so. Peter's et al. is the most informative and explains a lot of their decisions, but the cast's is probably the most fun.)
Maybe I'm just completely clutching at straws here in defense of what I think is the most moving piece of cinema I've seen this year, but I think that Theoden's moments of despair are intended to kind of clue the audience in to the fact that there really is something to fear in the siege. I can't remember what Theoden's character was like in the book (I'm rereading The Hobbit and The Lord of the Rings as we speak), but I have always liked the old saying that goes something like: "True courage is when you are afraid of what you must do, but you do it anyway." Y'all can gripe all you want about how Theoden seems weaker than he does in the book; to me, he just seems more human.
God forbid a screenplay adaptation attempt to create some audience sympathy for characters than can come off as a little stiff in their original medium.
If you want something that mimics the novel more, try the excellent BBC radio play. Just put it on the right chapter and mute the appropriate scene in the movie. Sure the dialogue won't match up to the actors' mouths, but at least Tolkien's characters would be preserved.
On a lighter note, I remember a lot of posters on these boards worrying that those who had never read the book would be corrupted by this "bastardized" film version. Since she saw the first part, my wife has read the book, which she had never intended to do before. This year is also the first time that FotR, TTT, and RotK have been checked out more than the Harry Potter books by the students at the middle school where I teach. Sounds to me like PJ has perpetuated Tolkien's greatness instead of diluting it.
Ah well, I would never have read Gone with the Wind if I hadn't seen the movie first, but I certainly think the book is superior. I just see Vivien Leigh and Clark Gable's faces whenever I read a scene with Scarlett and Rhett.
