Preconceived notions have little to do with the dislike of TLJ that I've seen.
Sure, it swerved from preconceived notions in a few obvious ways, but the problem wasn't that it subverted expectations, it's that it did so in a way that didn't actually benefit the film at all, on the contrary it largely detracted mostly for the sake of trying to be different. Unexpected doesn't equate to good, especially when it's at the expense of a logical payoff to a setup. It still bothers me that it seemingly went out of its way to piss away every single setup from TFA. I wouldn't have cared where those plots went, as long as they went
somewhere. Instead they were like "haha nope, fuck that" every single time, and little nothing of value in its place. It became predictably unpredictable.
But worst of all for me was the cringey sitcom humour that undermined the importance and emotional weight of the first 2/3 of the film. I dreaded every single scene inevitably ending with a dumb one liner that would just crap all over it. Yes, Star Wars has always had a good humour element that is an important part of the formula, but the style in this film broke the fourth wall for me and took me right out of the film literally from scene 1.
Overall, there's the lack of continuing on from TFA effectively, a very weak and uncompelling story in its own right, and doing a poor job of setting up something for the next movie that I care about. This movie has highlighted the problem with Disney's approach to the franchise, with no grand plan in advance for the trilogy. TLJ has such an inconsistency with the franchise, in tone, character, plot, and world.
I know a film is bad when it actually makes me glad that JJ is taking over again.
That's not something I'd ever think I'd say after his treatment of Star Trek.