I don't see how. They would have to start from scratch for the assets, but they would have a well known template to follow, and honestly FF7 was NOT a huge world with that many unique places to visit in comparison to today's games. There was also alot of back tracking and revisiting, flashbacks, etc. Hell half the game was just FMV.
It might have been a big budget busting game in the 90s, but it would be a pretty crude game to remake today esp with the 100s of 3D artists they have these days.
They make games today that eat up an entire Bluray on a regular schedule like its nothing. FF7 was 2.5 CDs, most of it duplicate FMV files so you didn't have to swap discs.
As much as I don't really care for it, I don't see why they don't remake it if they are hurting for cash. I bet it's forever lost in IP legality limbo with Square Enix not being the same people/company. There is no other explanation.
Sorry for the late response, but I think the FMVs were part of the expensive part. Rendering that much today, in HD, would be a big undertaking. If they wanted to match the quality we've come to expect (think Pixar level), it would cost a good chunk of change for that much. Plus, they'd have to completely scrap pretty much all of the assets except maybe the music (if they even still have the lossless score).
I am sure a lot of people would buy it, but they'd end up disappointed after playing it (which is probably the reason it really won't get a remake). It wasn't a particularly good game, in fact, it ranks as one of the lowest in the FF series for me. Most people just remember it because it was their first FF and the first game to really have that kind of scale for them.
As far as this HD remake of KH goes; I will most likely never get it. I didn't like the original KH. Don't get me wrong, I loved the idea, and the gameplay was good, I just didn't like that I had to do all kinds of garbage just to get my ticket to ride the train and have Disney characters coming out of every orifice. Plus, the story never really grabbed me and the main character was annoying.