I actually got to see it last night! Finally!
I know it's hard to compare a movie to the original story (it was a short story by Annie Proulx) but, the beginning lacked A LOT! It just didn't have the character development that it needed to understand how and why they fell in love. That makes it harder to understand the whole rest of the movie. Even I was surprised when all of a sudden they were having sex, and I knew it was going to happen! The story took a lot of time developing their relationship with them talking, becoming friends, growing closer.... If somebody just walked in off the street not having known what it was about...which I'm betting thousands of people did...they would think it was just about 2 guys who fucked each other. And that's too bad, because the story really was a beautiful, sad, love story. The movie was really long...they could have cut out 5 minutes of other stuff, added that time in the beginning, and ended up with a much better love story.
You start to realize later how much they mean to each other, but it just doesn't mean as much when you don't get it in the beginning. The ending was really good...broke my heart. Again.
'Brokeback Mountain' was actually one of THE BEST stories I have EVER read! It's stuck with me all these years. If you are a reader, you really should read it!