On thing you’ll notice about all of these: most were changed because the audiences hated the original scenes. And for good reason.
Some storytellers think that happy endings, where Good triumphs and Evil is defeated, are beneath them. They think that a story is more “insightful” or “mature” or “deep” when the Good guys get slaughtered and Evil wins. (Or, worse yet, where the Good Guy who kills monsters is the real monster after all.)
Deep Blue Sea, to pick one example, should have ended with the culprit getting their just desserts. That makes a satisfying movie. Now, it was a thoroughly pinheaded decision to make the romantic love interest also be the bad guy (at least without providing a suitable substitute), but once you made that decision, the bad guy (or in this case, bad gal) had to bite it.
It would have been more satisfying for the real culprit to be someone who went behind her back and took things too far, and it might have been more satisfying for them to realize her malfeasance early, and the hero turn his romantic attentions to a woman who deserved them, but neither of those (eminently respectable) choices were made.
Writers need to stop trying to prove how clever they are, and focus on delivering a satisfying tale. And in satisfying tales, Good triumphs (after a long, grueling struggle), Evil is defeated, and the guy gets a girl who deserves him. That’s simple, basic storytelling.