I can't help but feel that, after seeing the downgrade ($1 in the buzzword jar) in the MS conference, there was no way they were going to run that gameplay more than they had to.
They know it's gotten worse, visually, and they don't want to plaster it all over E3. So they made a nice trailer instead. I guess it's better than plastering bullshit gameplay.
I saw a downgrade too but it wasn't that much. it seems more plausible now.