Things I liked in the movie:
Intern tossing in the car keys. I admit that I chuckled.
The Borg Queen from Star Trek showing up in the healing room.
Heimdall taking down that ship.
The black hole grenades.
The funeral scene. Some beautiful shots in there.
The cameo.
Thor tossing Loki out of the ship to shut him up.
"Why are there so many shoes?"
Hanging up the hammer like a polite house guest.
The irony of Loki's (apparent) sacrifice--I'm sure Coulson would have appreciated seeing that.
The fun and imagination and visuals of the climax.
The great slow-mo hero shot of Thor leaping at Malekith in the red cloud.
And I loved seeing Mjolnir trying to return to Thor regardless of his location.
Personally, I would have switched the two extra scenes. That GotG teaser really struck me like a cheesy old episode of Star Trek or something. If they give us a whole movie like that, then it might work--but out of context, it just didn't fit the tone of the movie.