I doubt it will happen this way, but I'd imagine if they go with what they set up for Episode VII they are going to have Luke turn evil for all intents and purposes. We're going to have a bunch of Jedi who survived Order 66 show up, and one of them will probably be Anakin's Togruta apprentice from the cartoon series.
I anticipate there will be a more diverse cast, due to popularity I'm guessing at least one major, or major supporting cast will be a Twi'lek. I also expect after all of the complaints through at the series through "The Old Republic Online" there is at least going to be one gay or lesbian relationship going on even if not in the forefront in order to score PC points and "apologize" for some official statements once upon a time that there were no homosexuals in Star Wars.
That said, given JJ Abrams being involved, I think we're going to see a lot of odd things left hanging in the first part of the trilogy. I doubt a full trilogy/story arc has been planned out, and instead he's going to wait to see what the fans say and which bits he drops tend to capture the imaginations of people the most, then he will run with the ideas. As a result the ending is likely to be a mess since he will create so many holes and plot threads/potential plot threads over the years that come the end there will be no possible way for him to tie them up.
For an ending to the series I am guessing that either The Force will be removed from/leave the universe restoring free will, OR we will see an odd role reversal where the Sith are presented as being the good guys in context (freeom, passion, etc...) and the establishment of a Sith Empire seeming like a good/upbeat thing in comparison to the altenatives. The seeds that will lead to the cycle of darkness, without actually going far enough in the storyline to show how this is likely to pan out in a thousand years or so. In doing this it will help spawn other media (like further MMOs and such) by justifying the whole "heroic Sith" thing people in various RPGs and MMOs are already gobbling up as a concept, especially since the whole "Jedis do not allow love" thing annoyed so many people.
That said the prequels shattered my expectations, so I'm not going in with any real hopes, I'll check it out as a sci-fi fantasy nerd, but I'm hardly going to get all excited just to see movie trailers for this or anything. I mean I got sold on "Phantom Menace" early on, seeing guys like Samuel L. Jackson (hot on his success in things like "Pulp Fiction") heavily promoted, and then wound up with bloody Jar Jar Binks doing slapstick, little kids racing "space jalopies", little kids flying space fighters, an admittedly awesome final lightsaber duel that was resolved in an eye rolling fashion (and ended with the death of the character played by the best actor then involved) and Samuel L. Jackson was hardly in any of the movies at all despite standups, posters, and action figures of him popping up everywhere. The dude had one good scene in the entire trilogy and he died (and I might add I expected him to come back, because force lightning doesn't do that much damage that quickly, and one thing Jedi are famous for is being able to survive falls from crazy heights... I'm actually surprised Mace stayed dead, especially seeing as Obi Wan basically got shot off a lizard, fell off a Waterfall, and continued to live... but well... then again I suppose the whole pre-destined metaplot means The Force wanted Mace dead so it wasn't going to save him). The point is more Star Wars is big news, but the series is actually working against previous disappointments.
One thing I've actually hoped JJ Abrams might do is some kind of quick TV special or something to show off some of the stuff he's working on. It might be interested if we got oh say.. a new "Star Wars Holiday Special" directed by JJ, doing it right, and showing us some of the people he cast in character. To be honest with an iconic property like this I might try something like this given the previous failures to get some feedback to see if my ideas were at least on the right track. Granted getting another special done with some of the old cast (Harrison Ford in particular) might be rough. Still having the old guard hanging out with the new guard celebrating Life Day, and say telling tales (little skits about their back story or what they were doing between the old movies and the new) might generate important feedback. That way if people loathe a character that is doomed to be the next "Jar Jar" if it launches they have a chance to fix it before they fully film an entire movie with this guy running around screaming "Meesa So Scared" and grabbing fruit with a frog tongue.
