I was so certain that not including the Scouring would ruin the whole trilogy. I complained loud and long to anyone who would listen (which list grew shorter over time -- go figure) that by leaving out the Scouring PJ had missed the WHOLE POINT of the story.
I was wrong. I admit it. The end of the movie works just fine -- that scene in the bar, the four of them look around, see hobbits getting excited over giant pumpkins, and clink their glasses in silent salute told so much. It was a classic case of something a movie is better at than a book. You couldn't write those performances, the emotion carried in their faces. You need a sequence to show the emotional transitions, you need story to illustrate what's happened to these characters. In a movie, we can see it. We don't need a sequence of events to illustrate it for us -- it's right there on the faces of Billy Boyd (standout performance of the film, he was), Dom Monahan, Sean Astin and Elijah Wood.
He showed me what I thought would take the Scouring to illustrate, and he did it in one shot.