The Zahn trilogy was sucessful in the 90's because it was the further adventures of Luke, Han and Leia and the Rebels, or now New Republic.
Nobody cares about Hayden Skywalker/Vader, or any of those prequel cardboard cutouts supplemented by videogame graphics.
Now that i have seen how bad the prequels are and how he ruined the originals i am almost glad their is no episode 7, episode 7 would be as bad as crystal Numbskull, only worse because it would have been directed by Lucas not Spielberg.