We know for certain that we will be getting at least two spin-off films in the near future. They will be released between Episodes 7, 8, and 9. Lawrence Kasdan and Simon Kinberg are writing them. What we don't know is everything else. We don't know what they will be about, who's directing, or which writer is writing which (try saying that 5 times fast).
But there have been some rumors. I'd like to take a look at some of these as well as add my own thoughts on what would make a great spin-off.
I think we can safely assume that Boba Fett will be one of the two spin-offs. There have been plenty of rumors about it, including speculation that this is the spin-off Lawrence Kasdan is writing. That rumor also says that it will re-invent the origin of Boba, so he's no longer a clone of Jango.
I'm not okay with this idea at all. Although I love the mystery surrounding Boba Fett, it is clear that George intended Jango's clone son to be the masked man. This is evident if you watch the animated Clone Wars, where his future as the best bounty hunter ever is clearly foreshadowed. George also substituted the voice of Boba, in Empire, with Temuera Morrison's voice. Clearly they are the same person. The only way I would be okay with this rumor is if it took place after Return of the Jedi, when someone somehow extracts Boba's armor from the sarlacc pit.
I really want to see a showdown between a young Boba and Cad Bane. In the Clone Wars, Cad Bane is the best bounty hunter in the galaxy. By the time of the original trilogy, that mantle has passed to Boba Fett. I want to see the where, when, and why of that.
This is another spin-off I think most of us would like to see. I don't think it will or should follow the plot of the A. C. Crispin novels, or Brian Daley's novels. I think it will be original, and one of the things we will see is his meeting with Chewie, and why Chewie owes him a life-debt. Not much more to say about that.
Okay. People have been freaking out about a Yoda origin story. Most don't want to see it. We know nothing about Yoda's homeworld, his species, or anything about his past. People want that mystery to remain instead of showing us everything.
First of all, that's not what I think they would do at all. Yoda was probably brought to the Jedi Temple at a young age just like everybody else. We don't need to see his planet or know his species. If they made a Yoda spin-off, it would probably focus more on how he became the most respected member of the Jedi council. I'd love to see him take a bunch of Jedi Knights on a dangerous mission or something. Maybe the mission could be to Dagobah, and we'll learn more about the origin of the cave.
This was just a small rumor, but I think it's a spin-off we would all like to see. Ewan McGregor has also expressed interest in putting on the robe again. This would likely take place a few years after Episode III. Maybe it could involve the return of Darth Maul, since we're still uncertain what happens to him after The Clone Wars. Maybe Ahsoka could make an appearance as well. There are so many directions they could take this spin-off.
There is a recent rumor that Pixar would be making a Star Wars film. I think this is a good idea, but I highly doubt that it will be one of the two spin-offs. If we get a Pixar film, it will be in addition to what we already have. We know almost nothing about what this could be about. I have gone on record before as wanting animated adaptations of existing EU stories.
This would be a great opportunity, though I kind of doubt that Pixar would adapt anything. It would be an original story. If there are any animated adaptations, they will likely be 2D animated films released directly to DVD/Blu-ray, like DC Comics and Marvel have done.
Other Great Possibilities
This is a spin-off I would love to see, a film all about Vader and his time hunting down Jedi. Vader has one of the best psychological profiles, and those would translate beautifully to film. It might even make a better mini-series, where each episode is a different Jedi that Vader had to hunt down. It could end with Vader hunting down Ahsoka. Just imagine the character development you could have with that. Also, if they do a film about Vader during the dark times, I want Christopher Nolan to direct it. That's a film I would pay triple to go see.
I don't think this will happen anytime in the next 10 years, but it would sure be nice to have a film taking place in the Old Republic era. We might get more video games since EA owns Bioware, but I don't think there will be a movie until the sequel trilogy is over.
I've already mentioned her twice, but I think everyone would love to see a film about Anakin's padawan, Ahsoka. We don't know anything about what happens to her after the Clone Wars series finale. The film doesn't have to be her final end, but it would be nice to have one more adventure with Ahsoka. Preferably live-action.
This won't happen if the sequel trilogy decides to re-write the existing EU, but it would be a great spin-off to make if they don't. If indeed Luke is married to Mara Jade (or was married to her) when we see him in the sequel trilogy, audiences will want more background information on the character. There are the books, but not everyone is familiar with them. And not everybody is going to read them. A film about Mara Jade would probably be best if set right before the original trilogy or right after.
We are likely to get many new characters in the upcoming sequel trilogy and spin-off films. Although Kathleen Kennedy mentioned that the spin-offs would not intersect with the sequel trilogy, I think it's likely that some spin-offs in the future will focus on some characters that we haven't seen yet.