They should totally have as many elements from the Expanded Universe as possible. Han & Leia's twin children should slaughter each other. Snopes should be a clone of the Emperor. Luke should turn evil, and immediately clone himself, because that's what you do when you're evil. All the Moffs should go around on their Moffship holding Mofferences. Boba Fett should be alive and training Rey in the highly secret killing art that uniquely only Boba Fett in all the universe knows, called "a feint". There should be Force immune space vampires! And of course, the Zerg. And they should reveal that Han & Leia had a third child and then he should be killed off as well. Luke should die alone and miserable, and his grandson should become a heroin addict.