1- I did not read the books, although I was familiar with the storyline and some of the characters. I did read half of the hobbit.
2- The plot was confusing, the characters weren't pretty much developed (except Golum/Smeagol), it was hard to know what was going on if you didn't read the books.
3- Some friends of mine, who are Tolkien fans and read the books, told me they hated the way P.J. changed the story.
4- It was too long, and not very well paced to cope with that length. Titanic is a 3 and a half hour movie but you don't feel like it's that long. Same for Godfather II, Schindler's List, and other good 3 hours + films. At the last 10 minutes of ROTK, the whole audience was screaming "the end! the end!", and so was I.
5- Elijah Wood. That says enough. The only 2 films he tried to act were "Radio Flyer" and "Eternal Sunshine of the Spotless Mind".
I think Peter Jackson should go back to what he's best: funny gore films, such as Brain Dead (aka Dead Alive). "I kick arse for the lord!"