I just find it weird when public opinion about a movie gets so wrapped up in the business of it. Unless you're a producer, a studio exec, or some outside investor, who cares if there were budget overruns? Or when a movie flops, does that mean it's bad? When it does insane box office numbers, does that mean it's great? As trivia this stuff can certainly be interesting, but, imo, none of that should have anything to do with someone's assessment of how good or not-good it is.
In the cases of Waterworld and John Carter, gossipy gossip preceded their release and gave people a tidy, seemingly insider-ish opinion to have about them, and that was that. Oh, that movie? Heard it was expensive, and it flopped. Must be terrible!
But mention Blade Runner's budget overruns, disastrous test audience reactions, and bad box office numbers, and that's just studios and mainstream audiences not knowing a great movie when it's in front of their faces!
Again, the trivia and the production details can be really entertaining (I definitely eat it all up). But it can also provide easy, knee-jerk meta-narratives that have nothing to do with film criticism or analysis, particularly before the damn thing even comes out.
(Also, not really defending Waterworld here, but at the very least it's a supremely weird movie and a huge swing, which is more than I can say for some MCU movies)