Dream Sequences in Age of Ultron?

According to this article from The Mary Sue, Scarlet Witch uses her powers to show each Avenger their greatest fear...which explains a couple of things.

1) The Hulk/Hulkbuster fight. Wanda sneaks up on Bruce and does her whammy, resulting in the battle dorks like me have been waiting decades to see.

2) This scene from the trailer with Cap back in the '40's. It also explains how Peggy can appear in this film.

3) The Black Widow/Red Room/Ballet scene also from the trailer.

4) Finally, it explains the broken shield. This is Thor's greatest fear, as seen from inside his head...not reality.

This all makes sense. How else can vital and essential backstory happen in a blockbuster film without the necessary flashbacks?