When Disney bought Lucasfilm and started on their journey to producing new Star Wars films, one of the first things they announced was that they would be ditching the Star Wars Extended Universe saying that none of it would be canon. This initially pissed a lot of fans off because the Extended Universe is full of great stories and characters.
There are actually many reasons why they decided to drop the Extended Universe and rebrand it into what is now called Star Wars Legends. Lucasfilm originally released a statement explaining why, but Star Wars Story Group member Leland Chee got a little more specific explaining that one reason came down to Chewbacca.
Why Chewbacca, you ask. Because Chewbacca was killed off in the Extended Universe and they wanted to play with that character in the films. While talking with SyFy.com, Chee, who also oversees The Holocron, which is basically Lucasfilm’s official version of Wookieepedia, had this to say: