the December King said:
No, it's cool, I didn't really feel pressured or forced to change my stance. Alien, at least to me, WAS the better movie of the two. I totally get that these are opinions, we good. I also enjoyed Prometheus, is all.
Cool

Although now that's out of the way, I agree with your point about classics (and horror movies) not being immune to stupid, but I disagree with your given examples and I believe you could've done much better.
For example, in Alien... I'd just love to know if the scriptwriters have ever actually chased a cat who
really didn't want to go to the vet before (cat Underworld) or tried to handle one while the vacuum cleaner is on (cat Cthulhu). I'm a cat person, I love cats (see my avatar), but to think that Ripley would have purposefully gone out of her way to engage in a day-long ordeal with Mr Jones (and that it didn't end up being a day-long ordeal) while there's a giant screeching penis monster stamping across the hallways, a loud-ass alarm and random hissing steam vents, is beyond ridiculous. Sound in space? Cold fusion bombs freezing volcanoes (ST:Into Darkness)? Fuck that noise, this is the shit that gets me riled up, right here. Nevermind that she didn't lose a finger or an eye in the process of stuffing him in a cage (cat DMV).
/end rant ;D