I'd buy it. When they released Crisis Core, I was hoping they'd release FF7 later with Crisis Core graphics.
If Square Enix remade it though, I'd want them to do just that. Remake it and don't try and change things that they think might make it better. End game content is fine, bonus dungeons that only become available on completing the game, but no major game ruining changes. And do some quality assurance. FFTactics and its slowdown on the PSP, FF4 Advance and the many, many, many, many bugs, glitches, and slowdown.
Final Fantasy 7 isn't the best Final Fantasy in my opinion. I think most people who think so started at FF7. It's still a really good game, so I have no problems with them releasing a remake.