One of the very few "director's cut" editions that improved a film was Blade Runner, and that mostly by taking things out (Ford's awful voiceover, demanded by the studio and recorded basically under duress).
I think that only works if you have seen the narrated version first. I tried this with my sons, showing them the Director's Cut first, and they had no idea what was going on for a lot of it, especially the very long atmospheric shots of Deckard and Gaff in the flying car not talking to each other.
