
“Rogue One” is more than just a new “Star Wars” movie; it’s also the very first “Star Wars” spinoff movie. It’s an exciting development for the 40-year-old franchise, and its first trailer has us excited as hell for what not only this movie, but others like it can bring to the table.

1. Added depth without added commitment
What was great about the old Expanded Universe of “Star Wars” novels and comics and cartoons and video games was how all that stuff fleshed out the franchise. The “Star Wars” saga (the numbered episodes) takes place across an entire galaxy, but we get only a very narrow view of it. Side movies like “Rogue One” that don’t have to directly interact with the “saga,” however, offer depth for more casual fans who don’t want to get into all those other platforms.

2. Daring cinematic takes on the franchise
Likewise, opening up the film series to these side stories allows filmmakers to weave the kinds of narratives that would never appear in the saga. From what we know about “Rogue One” so far, it’s a “Dirty Dozen”-style heist to steal the plans for the original Death Star. That’s not the kind of thing we expect from a “Star Wars” movie, making it a great idea for a “Star Wars” movie.

3. Moving away from the saga
In the seven “Star Wars” movies we’ve seen so far, everybody either knows everybody else or they’re related to each other — that’s why it’s call a saga. But “Rogue One” steps outside the saga, both in title and with its characters. “Star Wars” is a big place and we finally get to feel that onscreen.

4. Building a monster cast
Felicity Jones, Forest Whitaker, Diego Luna, Mads Mikkelsen, Ben Mendelsohn, Donnie Ye, Wen Jiang, Alan Tudyk — this is probably the greatest cast ever assembled for a “Star Wars” movie. It’s a confluence of awesome made possible by not having to lock everybody down for a million movies. It’s hard to believe they managed to put together this group even after seeing (most of) them in the trailer.

5. Expanded character types
“Star Wars” movies have always been very black-and-white in their morality, and the characters they focus on reflect that. “Rogue One” goes gray. Our hero, Jyn Erso, is rebellious in a way that grates the morally righteous Rebel Alliance, and her crew is comprised of more of the same. In a side movie, we aren’t limited to heroes who walk the straight and narrow, affording us the kinds of characters we wouldn’t normally get to spend much time with in a “Star Wars” movie.

6. Old movies get new context
The “Rogue One” trailer opens in a particularly exciting way, bringing us back to the Rebels’ secret base on Yavin IV. It’s a famous location from the original “Star Wars” film, but we weren’t there for all that long back in the day. This is another great world-building service the side movies can provide — not just fleshing out the universe, but also specific places and events. It gives more meaning to the stories we already know. The prospect of “Rogue One” giving greater context to “A New Hope” is tantalizing.