I wish Kuiil hadn't died
It seemed so unfair. He was a surprisingly likeable character, and his phrase "I have spoken" has already become an internet meme. https://i.imgflip.com/3ha5kt.jpg
His tinkering with that assassin robot was an incredible feat, as was re-training it to be helpful.
It just seemed so unfair that he got shot and killed by those asshole idiot storm-troopers :(. I was hoping he'd stay on as a regular character.