Plenty of people had plenty of thoughts after Disney bought Lucasfilm and declared that the extended universe -- the books, comics, and other non-film media that had been the backbone of the franchise for decades -- were no longer official canon. While there are many different opinions on whether or not this was the right decision, one member of the Star Wars Story Team, Leland Chee, believes there was one specific reason why cutting the EU out was a good idea: Bringing back a very important Wookie. Speaking in the Fandom Files Podcast, Leland Chee explains one interesting reason why Lucasfilm may have made the choice it did. He says:
For me it came down to simply that we had killed Chewbacca in the Legends -- a big moon had fallen on him. Part of that [original decision] was Chewbacca, because he can't speak and just speaks in growls, he was a challenging character to write for in novels. Publishing had decided they needed to kill somebody, and it was Chewbacca.
But if you have the opportunity to bring back Chewbacca into a live action film, you're not gonna deprive fans that.There's no way that I'd want to do an Episode VII that didn't have Chewbacca in it and have to explain that Chewbacca had a moon fall on his head. And if we were going to overturn a monumental decision like that, everything else was really just minor in comparison.
In 1999, the novel Vector Prime by R.A. Salvatore sees Chewbacca sacrifice himself to save Anakin Solo, the third child of Han and Leia. Anakin Solo is a teenager during the events of the novel, and so any movie that was set in the same period of time that The Force Awakens was set, which would be necessary due to the ages of the original trilogy actors, would have to be set after the death of Chewbacca if it were to take the extended universe into account.
Leland Chee wasn't part of the Star Wars Story Team at the time that the decision was made to excise the extended universe, but as a member of that team now, he certainly thinks about Star Wars in a way that works for Lucasfilm, so it's certainly possible that this explanation was at least part of the calculus that went into the decision at the time. It would make sense. Chewbacca is as popular a character as any other member of the original trilogy cast and most people never read the books and wouldn't be aware of the Wookie's fate there. It would have been anticlimactic, and frustrating, for many, to go to a new Star Wars movie and discover Chewbacca had died off-screen in between films.
It's also likely that the reason for Chewbacca's death played a part. If there had been some grander story reason for the death that made sense to hold onto, perhaps they would have, but according to what Leland Chee said on the podcast, the reason had less to do with telling a story and more to do with removing a character who was problematic to write for. You can check out the full Fandom Files podcast over at Syfy Wire.