To be fair, I wouldn’t have minded seeing Chewbacca die in Episode 9, the fake out death they did in that movie really bothered me.
Chewbacca has always been more of a animal sidekick rather than a character, so seeing him die in particular wouldn’t have been so bad (especially if it was used properly as a way to grow Rey as a character, which seemed to have been the original intent).
And I mean, even within the context of LEGO, Bionicle had Matoro die, and look in what a high regard the Bionicle story is held now because of that. With Bionicle, the writers clearly knew that they were righting a story, not a toy commerical. With Ninjago, it is kind of the other way around, for better or worse.