Plot points I guess are fine, as long as we don't add too much about them. Here's a good Roger Ebert quote on trailers: "Trailers. Have nothing to do with them. Gene Siskel hated them so much he would stand outside a theater until they were over. If he was already seated in the middle of a crowded theater, he would shout "fire!" plug his ears and stare at the floor. Trailers love to spoil all the best gags in a comedy, hint at plot twists in a thriller, and make every film, however dire, look upbeat..
As long as we don't break any of those rules we're good to go.
EDIT: AYBGerrardo's outline sounds awesome, I would suggest though to have this line right before Veidt's: We were supposed to make the world a better place
(Dan). We should also make it sound echoey, there are plenty of free programs that can do this pretty easily.
This TV spot is pretty good, click here
to check it out. Your trailer was pretty similar to that near the end, or at least I got the same vibe.
Technically you really don't need plot elements, it depends on what kind of trailer you want to make. A teaser trailer, like the first Watchmen trailer, is just there to make the movie look damn cool. Loads of people loved the first trailer, and no one knew what the hell it was about. It didn't have many themes either, but man was it cool. I think we're gunning for something more like the theatrical trailer (based on the outlines). Which is fine too. Maybe something with a good balance between cold war, and assassination, even if only for the fact Snyder already nailed the pure assassination angle.