I already posted all my reasons in another FFVII thread. Suffice to say, FFVII is a game that both hasn't aged well and has many plot/character holes that can be fixed. Even the creators have admitted this and said that's why they made Advent Children and Crisis Core. The latter in my opinion being 10x better than the actual FFVII.
As much as I'm not a fan of FFVII, if they could remake, and fix everything, I'd probably be a bigger fan of it. If they do like they did with the FFIV remake on DS....I seriously say just skip remaking it. If you could even call FFIV DS a remake....