And I've always had trouble role-playing in the Star Wars universe, because ultimately, PCs have only a limited degree of ability to change the world - and small people making big changes is one of the primary themes of the setting. No. Really. Look at the original trilogy. Look at the (surprisingly low) power level of the Jedi.
And the reason we can't change the setting as PCs is because so much of it is already established. We know that the first Death Star is going to be destroyed by Luke. We know that a small Rebel strike force is going to take down the shield generators on Endor. And, while we can participate in these, we can't change them most of the time.
The Expanded Universe has actually made things worse for that, by establishing the outcomes of most of the battles and skirmishes. The novels and comic books have filled in more and more, leaving less and less available to GM imaginations.
Yes, good GMs can find ways to include PCs all over the play. According to Timothy Zahn, the Executor ran into the Death Star because the Emperor stopped upgrading the competence of his troops via the Force. But what if there was a team of Rebels aboard who sabotaged its controls, too? It's a suicide mission, to be sure, but clever PCs might find a way to survive ...
Again, though, that's not changing the established universe. That's just participating in an already-fated outcome.
So I was really excited when Dark Horse announced that they'd be publishing The Star Wars. It's a one-off comic (a limited run of four issues, IIRC) that went back to George Lucas' first draft of what would eventually become Star Wars, Episode IV:A New Hope. It's Star Wars without all that pesky Canon. Well, almost.
But this isn't the only universe with a great deal of established canon. Every licensed super hero game has had to deal with canon - but, since the original publishers have a history of rebooting that canon from time-to-time, it's not really been as much of a headache. Star Trek has mostly avoided the universe-shattering storylines and tells mostly stories about one ship and her crew, leaving much of the rest of the universe open.
But every licensed game has to decide how to deal with canon. Either in the book itself (direct from the publisher) or at the table (via the GM). And there are a few options:
Canon is inviolate.
This, depending on the universe, can strangle games. The GM does their best not to break canon at any time. It's good because the players know what to expect from the game and what is going to happen. It's bad because players can feel constrained. And what happens if something new comes out in six months or a year that contradicts the game's canon?
Canon is flexible.
Maybe small changes are possible, but the main story arc is going through as expressed in other media. This is good because players like being able to impact the world and they like knowing what to expect. It's bad because sometimes those small changes can lead to much larger changes later.
Canon is cherry-picked.
I'm guilty of this one, sometimes. Especially with Star Wars. "The original movies are canon. The Zahn books are canon. Nothing else is." It's good because it can really open up the setting. It's bad because players often want other favorite things from canon included. Or other things excluded.
Canon is inviolate until
This is another form of cherry-picking. But it can also open up the world up to players. If, for example, the game picks up with the destruction of the second Death Star, then the movies are in but the Zahn books are out, then the entire future of the galaxy is in question.
This is a universal reboot. There is no canon.
Pretty self-explanatory. The good part is that the PCs can go anywhere and do anything. The bad part is that they don't know where to go or what to do without guidance from the GM. The fact that they can't rely on their knowledge of canon is a mixed blessing. This one requires more trust of the GM than the other options do, because if you build your character based on Jedi being warriors and then discover that they're just seers ... well, you're going to be pretty frustrated.
I tend to prefer the cherry-picking option, because it does a good job of setting expectations for players without running too much risk of alienating them.
I suspect that the team behind Episode VII started running into canon-related problems pretty quickly, which is why they made that announcement a few months back about the Expanded Universe being non-canon, now. And then showed off that they are apparently actually cherry-picking.
Meanwhile, I just heard thunder and saw some lightning, so I should shut down and walk away from the computer, now.