first off, for every movie that is made there exists like 30 different versions of it in the cliproom where the editors choose the best version of each scene that really sets a consistent mood throughout the film and makes it feel like a continuous piece. there are tons of subtle differences that may not matter much per scene but that'll greatly affect the overall feel of the film. reconstructing this in your own version with different actors is hard to do, especially considering the fact that a lot of the subtle tension relies a lot on the actors personalities and charisma, and how their appearance comes off. thought not often, i can recall a few times ive gotten frustrated over flicks where the actors are clearly trying to pull off a style that emulates a famous character.
this is true but in your hypothetical we're talking about a shot for shot remake. in the non-hypothetical, we're not talking about just frustration, but some element that makes you think it's ABSOLUTE ASS.
secondly, language is an extremely important aspect and a lot of shit that works in one language simply does not translate with the correct emotion or feel. being fluent in two languages myself and partly knowing a couple more i know that there are phrases, words, concepts and even grammatical styles that simply can not be translated into another language whatsoever. a lot of the feel of the dialogue is directly linked to the manner it is presented, the manner it is written and the language it is written in. first off, if the language it is translated into dont give off the same aura over what's being said, if the words can not be directly or closely directly translated without coming off as really, really wrong, then you have to restructure the entire sentence and most likely the entire scene to make it work.
yeah but that's why I brought up Nabokov's frustration with translation. in a movie that isn't dialogue heavy like REC, where there probably isn't a single really quotable line; or actually, let's change tacks. if the movie had some moment of sheer poetry that loses effect in English, or a linguistic irony that would be lost, maybe. as an example, Spirited Away has a scene where she steps on a bug so this grandpa spider guy separates her fingers to dispell a curse. subtitled, this isn't explained. dubbed, it was, and it was just a little BIZARRE. however, I see no such effect in REC. granted, I havent seen it recently, but when I did it had no particularly spanish scenes or language scenes that would be lost by a dub remake.
I think you're granting too much to subtlety in a movie like REC, already not the greatest to begin with. something like my shitty articles on GW can lose effect for non-American GW members (you might not even know what a FAFSA is for example), so I know what you mean by percieved audience and the shift. but if we're looking at this realistically, REC had very little of that percieved audience. it's not a cultural piece in any meaningful way.
in a little twist of irony its actually more believable that a news crew would do a useless fluff piece on firefighters in America thanks to 9/11.