I agree with everyone here, the fact that it was most people's first JRPG made a huge difference, for me it was FFVI, and it's really hard for me to have another Final Fantasy game challenging the status of that game in my heart. Not to mention the technology advancement. I remember myself saying "three discs?" when I was young, as well as the marketing campaign when it was coming to the West as being the system seller in Japan.
Obviously everyone has different tastes in games and their plot, but I do think FFVII had a very good plot. It was engaging overall and Aeris/Aerith death also was unexpected enough it made the game special for a lot of people. I think FFVII is one of the games you can say you don't like it, but you can't really honestly say it isn't a good game, generally speaking.