The Marvel Universe is getting darker and darker. Iron Man 3 looks dire and Thor: The Dark World is literally taking us deeper into darkness. And I don't know about you, but I like it.
This teaser doesn't serve up much story, and it shouldn't. It should give you a feel for the emotions that will pop up during the movie. I like the subtle things like Sif giving Jane the death glare. But I also like the not-so-subtle things like Thor on his knees shouting "NOOOOOOO!"
I think it looks good.