It's easy to knock the LOTR Movies, but it's always easier to knock than commend. I know PJ and his team made very good movies, no easy task, even if I have myself a tendency to blindly support the "knocker" party. Anyhow, the changes he made to the story seem to be the most contentious. So, to be fair to PJ, why don't we think about the things that PJ "added"" to the story which Tolkien (if he was alive) might have been persuaded to "add" to any revision of his book.
Improving "deletions" might be noted too. For instance, should Tolkien have excised things like the Barrow-wights from LOTR?
I'll stick my head in the noose and say I think having Arwen in place of Glorfindel in "Flight to the Ford" was a superb idea (even if it's execution in the movie left much to be desired - later scenes between Aragorn and Arwen were mostly brilliant, I think!)
Anyway, what do others think?
Odo
