(Here's a combined trailer of all the footage from the official trailers)
Back in the mid to late 70's the "New Wave" was in full force. Downbeat endings, "black and gray morality" (which can be good if handled well, at least as a change-up from more clear cut items) or worse "black and black." Those were the tone of Science Fiction.
Then, fairly close to each other, two movies came out which took an entirely different approach: Lucas' "Star Wars" and Spielberg's "Close Encounters of the Third Kind." The rogue was given back his heart of gold. The callow youth could be the hero of the piece, not ground down by the world weary cynics. Heroes who are actually heroes fighting bad guys who weren't so "sympathetic" that you couldn't tell hero from villain.
It was a refreshing change. And the result was that, for a time, it became OK to have good guys who were good guys. Bad guys who were actually bad and not just "oppressed" or "victims of their backgrounds". You didn't have to wonder who to root for.
Today we're kind of in a similar position. One of the best selling series, for young people is The Hunger Games. Black and Very-Dark-Gray morality, little really to choose from in the sides, and (no spoilers) that's shown pretty clearly in the ending. And in printed SF? So much "humanity is a plague" stuff. Bleah.
Sarah A. Hoyt started the "Human Wave" movement as a counter to that. I joined in full fervor because that's the kind of fiction I like to write. That's the kind of fiction I like to read.
What I'm hoping is that maybe the new Star Wars will be able to do it again.