There are certain elements of SW that will be indispensable for the sequel trilogy, and others that we may want but are probably not completely required. Let's assume that Episode VII features Luke as a starting point. If Luke is in the film then by extension the film must feature or at least make reference to their absence: Leia Han Chewbacca R2-D2 C-3PO I actually think the film could succeed without even a mention of Lando. (It might be disappointing, but I don't think it would create a hole that hurts the film). I don't think other characters of the Rebellion are a must either, as in: Mon Mothma Admiral Ackbar Wedge Antilles And as much as some may want it we don't need Boba Fett or even a reference to him. Events that must be referenced (even if indirectly): The destruction of the Empire. The death of the Emperor. The redemption of Vader. Depending on the level of underworld use in Ep. VII it may be necessary to at least indirectly reference the destruction of Jabba's crime syndicate. Destruction of the PT Jedi Order. The rule of the Empire. Current state of a galactic Republic or absence thereof. Concepts that must be referenced: Jedi (and of course what comes along with that: Force, lightsabers, etc.) Dark Side (perhaps not Sith, but I think you have to have at least the looming threat of the dark side). I imagine other things are probably a must, such as Yoda/Obi-Wan's training of Luke, etc. but that kind of depends on the direction they take as well. Then of course, if the EU is to be preserved at all you open up a whole set of items that would have to at least be referenced (Anakin, Jacen, Jaina Solo, Ben, Mara, etc, etc).