DBZ is weird in that people probably know the big story beats, the truly important stuff, but don't know/remember the little things in between. like, Namek blowing up is a meme at this point.
Kai also does subtly change some beats via the condensation of the show to manga only moments and the new improved translation. It's not quite REmake levels of fucking with people familiar with the other show, but it's got some serious "wait, did that really happen that way?" moments along the way.