Other scenes

Another very interesting scene was the one when Quicksilver dies. We see in the cinematic cut of Age of Ultron how Scarlet Witch screams in despair. However, it would have been a greater impact if the actual trailer scene was kept.

Another interesting shot, and quite a cool one, was with Black Widow and her brand new batons. Sure enough, we saw plenty of action with her in the movie, but maybe this should have been also kept.

Lastly

Lastly, there are two other scenes that didn't make it into the cinemas. One is with Ultron and the twins, as he turns toward them quite dramatically.

And then there is the wide shot with all the Avengers in the Quinjet. The dramatic moment would have been enhanced if, in the finale Age of Ultron cut, Thor faced the camera just like in the trailers.