I don't care about voice acting all that much. One of my biggest annoyances with the game is sometimes you have to be in a VERY PRECISE spot to use something-a ladder, whatever. Maybe this is just a problem with the PC port, but it is terribly annoying.

What everyone else has said, basically. I'd love to see a remixed soundtrack, maybe re-recorded to sound better and more orchestrated tracks, like "Aeris' Theme" and especially the orchestrated main theme from "Reunion." I haven't seen it, but maybe the content from "Last Order" could be added. Maybe the whole Shinra Mansion scenario expanded as a whole.

There's also this one bit, where you're meant to go to Gold Saucer to regroup before Temple of the Ancients. I can't recall ANY hint that you're supposed to go there. There's just a few points in the game where it's not exploration, it's "What on Earth is going on?"