I suspect you're right, though it definitely would not have been the same experience had it been produced to the 'standard' length. I haven't read the book, but even I could tell that it needed the time to develop all the threads which wove the story.

I'm not sure I'm a big enough fan now to see it again, but I'm glad I saw it, and doubly glad I saw it in the theatre as opposed to dvd. It's an AMAZING visual experience. (Though I could have done with a little less of the Glowing Penis of Doom. {no real spoiler}.) :-)