I would have been happy with just one movie.
And if anything, I suspect a lot of people couldn't help responding with the usual "pfft"s, and "meh"s, and snarky comments about Hollywood and money
, when they heard we we're getting more than one (though it's not like they won't happily pay to see all three films... in IMAX, in 3-D, and at 48fps if they're well enough informed).
For both Rings
and The Hobbit
, Jackson shared screenwriting credits with Fran Walsh and Philippa Boyens. So he did have his hands deep in adapting the material. There were a lot of changes made, and besides the practice of writing for the screen is very different from prose even with the most conservative adaptation (ask any author who thinks he can adapt his own work into a movie script). Left to their original narrative structure, the books would be almost unfilmable (maybe you could do it as a six-part TV miniseries). Not to mention the books themselves are so thick in detail that even reading them thoroughly most people are unlikely to digest everything that's in there. There are a wealth of illustrations out there that are considered 'canon' to the world of Tolkien, and readers would know right away if those weren't reflected in the film's designs and locations. Apparently not just anybody can illustrate Tolkien after having read the books. And the TV/DVD documentaries on what went into building Middle Earth for the films are frankly overwhelming.
Return of the King
is the longest Jackson/Tolkien film to date, clocking in at three hours and twenty minutes (I'm not counting the special editions). However long the script was (or whatever passes for a single linear script when you're shooting three films at once and changing your decisions all the way up through post-production), I would imagine Jackson has enough material -on paper or in his head as well as of film- that part 2 of The Hobbit
would have been at least as long prior to Jackson's decision to siphon it off into a third film. I'm not clear on whether the stopping point of part 1 has also moved or will move. Probably the films will average around 90-105 minutes each, not including bonus material re-inserted into the longer home video versions (if applicable).
I do think the extended versions of Rings
suffer from pacing issues, which is why they're not the official versions of those films (and the decision to break each one up between two DVDs/BluRays, so they can be enjoyed in manageable chunks, was a wise move). I believe Jackson has -at least- enough sense to not try to pad out three films if he didn't think enough material was there.