For me, Final Fantasy 7 will stand at the precipice of JRPGs. What makes it so great, for me anyway, is the whole package of characters, story and gameplay, with the obvious advantage also of being a game with loads to do.
Character wise, theres always something interesting. I admit, Cait Sith I still have a dislike for but the act at the Temple of he Ancients was a really great way to redeem the character to an extent. And it tied in wondefully with the story. The love triangle keeps things interesting, and gives the desire to see the 3 appropriate characters' flaws and merits.
The story drives the whole experience, with periods in the game where you learn a little more about each character. (Barrett in the desert prison, and Cloud/Tifa and even Sephiroth in Nibelheim). So not only are the charcters themselves interesting, but a further interest certainly develops from their individual stories as the game progresses.
Finally the gameplay meshes everything together. The Materia system is still in my eyes the most enjoyable and sucessful of the Final Fantasy ability systems (from the Final Fantasy games I've played).
So all I can really say overall is that a game has to possess all 3 of the above and excel in them to be separated from anything else. You've also got to look at who plays the game. Ofcourse an RPG fan is going to grasp the mechanics and the quirks of the game better than most, and so can appreciate them a lot more. Just look at how far the Final Fantasy 7 franchise has come, never mind just the Final Fantasy's in general.