If you could change only one thing about this game, what would it be?

Some aesthetic changes, including the NPCs

did he really say that? what an asshole

Make the ghosts more subtle. Their purposes was good if you're not a brainlet, but their implementation was kinda hamfisted.

I'd prefer a long initial loading screen between chapters than stopping every 10 seconds for tedium.

Wedge had it coming, to be fair.

Make the whole Leslie sewer quest in chapter 14 optional I guess? That was pretty fillery.
Or just get rid of most sidequests and make the game go for a bit longer after Midgar with playable Red, that would've been nice.

If you set it to Classic mode it goes FULL classic mode: everyone lines up and does turn based fighting

Give Cloud a faggy personality once he gets alone with Don Corneo. It was an option in the original but I'd make it mandatory.