Harmy said:

Yeah, ok, so you say yourself that the dialogues are dated - would it be a good idea to rewrite and re-dub them? Today, it wouldn't be that much of a problem to even lip sync the actors' mouths to the new dialog and it would make the film more modern and therefore "better," right?

The movie as a whole is a product of its time - and if one wanted a more modern version of the same story, well, that's what remakes are for.

If it works perfectly I wouldn't see why not. But that is utterly impossible. As it stands Harrison Ford carried both Mark Hamill and Carrie Fished in STAR WARS and if someone were to add new dialogue and lip-syncing and made it perfect it would boost their performances given some of the lines and the way said lines were delivered weren't all that great. As for remakes the ONLY way I would even give it a thought if it were better than the OT.