I'm intrigued by the expanded universe being rejected and a little bit confused about this as well.
I've read the Thrawn Trilogy, Jedi Academy Trilogy, Courtship of Princess Leia, New Rebellion, Truce at Bakura and the graphic novel "Dark Empire". I even read the childrens' novels was when I was 11 (can't remember what they were called though). In the foreword of Dark Empire, I believe it was Kevin Anderson who wrote that everything written for Star Wars had to be canon.
Also, no back story would really need to be written for Jacen, Jaina or Anakin. It already exists in the novels and if people really want it then they can go and read them. When Qui Gon first appeared in Phantom, there was no real back story for him as well as a host of other characters. They just rolled with the characters and went with it.
Drew Karparshyn wrote books based around the Mass Effect universe and the events in the book were mentioned in the game, but did not go into great detail. I think that if people read the Star Wars EU then there experience will be a lot richer when EpVII arrives. I know my experience of reading the books around Mass Effect greatly improved my experience when playing the games.