Apocalypse Now: Redundant is more like it. Why fix something that is perfect? I've never seen an Alien directors cut but the same reasoning applies here.

Terminator 2: I can't remember what it was called, but it was an extended edition from the double-wide silver Ultimate Edition. Some extra laughs for sure, and like you said, nothing that took away from the movie, so it was worth it. Plus, once you've seen it so many times (as I have) it's cool to see new stuff, like the terminator trying to smile :p