Oh, I think that more of the story could have been included in the movie. In one version of the screenplay which I found online, there were more things in that version of McMurtry's and Ossana's screenplay than what was in the final script of the movie.
I also say that since they show Ennis Del Mar's flashback of when they got blood on the shirts when discovers them in Jack Twist's boyhood closet as a scene early in the movie, they could have had Jack telling about his father urinating on him when he was a small boy when the guys were together at an earlier time. Ennis remembers that as a flashback when he is at Lightning Flat.
Oh, they would not have to show his father's penis in the movie; they could have just shown that he was undoing his pants and then cut to a little boy getting wet.
I just think that all of the action which is merely narrative when it takes place outside of Wyoming could have been done as a "voice-over" narrative, too.
I still don't understand why the other writers and the movie script had to have Ennis arrive in Signal in a semi truck, having hitched a ride with a trucker. In the screenplay, Ennis did not even know when he got to Signal; but, in the book, while Ennis is talking to Jack up on Brokeback Mountain, he does mention that his older brother lives in Signal.
Oh, I wouldn't have been surprised if Ennis had not called Jack, "little darlin" when they were up on Brokeback and being intimate.
Speaking of "intimate," unlike the movie, after Ennis gets into Jack's bedroll that first night in the tent, there was deepened intimacy before Jack took Ennis' LEFT hand and put it on his cock.
That was make to look rather awkward in the movie, with Jack lying on his left side with Ennis flat on his back behind Jack. Jack used his RIGHT hand to reach ACROSS Ennis to get Ennis' RIGHT hand and pull it across himself.
If Jack had actually done it like in the movie and knowing the character of Ennis, Ennis would not have had sex with Jack; he would have slugged him, giving Jack a cowboy "Attitude Adjustment."