Star Wars without Darth Vader doesn't make sense. I am not familiar with Zahn's Expanded universe but the only way it could work is if Leia turns to the dark side, I do hope J.J Abrams and the screenwriters considers this. Luke would replace Obi wan and Yoda as Jedi trainer and Leia would join the Empire and kill Solo (that would please Harrison Ford I'm sure!). Unlike Anakin who self mutilated his body to join the Emperor, Leia would become a femme fatale using her body to turn the rebels to the dark side... she would be "a great asset" and the franchise could go porno...

These two quotes form Jedi would be the perfect prophecy...
"You have that power too, in time you'll use it as I have, the force is strong in my family: my father has it, I have it... my sister has it"
"If (Luke) will not turn to the dark side than perhaps (Leia) will"

Anyway hope they're preparing a good script...