I don't know, if you look at the movie and see how all those songs fit into the overall vision of the story, none of the songs seem that superfluous to me. I remember when the movie was released and I saw it for the first time, I thought it was amazing how some of the background noises/dialogue that were on the album showed up in the movie. Now granted, they could mold the movie to make it fit to some degree, but still, the overall concept was pretty flushed out when the album was released. Originally, we just thought all the background noises and dialogue were there to make it more trippy (and I can vouch, that it worked).
The movie is a different animal.
I do like the album. All the songs are good. However, some are filler or don't drive the story or are unneeded subplots.
As an exercise, if I were to trim the wall to 3 twenty minute sides, I'd do the following:
1. I would not touch Side 1.
2. I would delete Empty Spaces and get rid of half of One of My Turns and half of Don't Leave Me Now. I would delete Goodbye Cruel World. There is no better way to end that part of the album than the modified last line of Bricks 3 "all in all
you were all just bricks in the wall." It says the same thing as Goodbye Cruel World in one sentence. This would remove 7 minutes of music from side 2.
3. For side 3, I would lose Vera and Bring the Boys Back Home. We've moved on from the WWII part of the story. This reduces side 3 by 3 minutes.
4. For Side 4, I would lose The Show Must Go On, and Stop for 2 minutes. I'd lose 2 minutes total from Waiting for the Worms and the Trial. That's 4 minutes on side 4.
Sides would go like this:
Side 1
1. In the Flesh?
2. The Thin Ice
3. Another Brick in the Wall, Pt. 1
4. The Happiest Days of Our Lives
5. Another Brick in the Wall, Pt. 2
6. Mother
20:11
Side 2
1. Goodbye Blue Sky
2. Young Lust
3. One of My Turns
4. Don't Leave Me Now
5. Another Brick in the Wall, Pt. 3
6. Hey You.
7. Is There Anybody Out There?
8. Nobody Home
22:13
Side 3
1. Comfortably Numb
2. In the Flesh
3. Run Like Hell
4. Waiting for the Worms
5. The Trial
6. Outside the Wall
22:15
It would fit on one CD, one cassette, and is right on the edge of 3 sides of vinyl.