Well this puts me in an unfortunate position. I didn't play on doing this, but it looks like I'm going to be defending Final Fantasy. FFVI anyway.
Simple fact number one: I don't like Final Fantasy very much.
I think over the past decade the franchise has become more and more about style over substance. FFVIII-IX were deeply hampered by overbearing narratives that were as unenjoyable as they were illogical. By the time we got the FFX the series had basically abandoned the premise of being games at all in favor of selling phenomenally bad interactive movies.
Simple fact number two: Even I struggle to deny that FFVII (the series magnum opus) is a good game. It has good gameplay, an interesting and logical story. Varied gameplay mechanics, crushing dept and an interesting world. FFVII was a good game.
Simple fact number three: EVERY SINGLE GOOD THING ABOUT FFVII WAS DONE BY FFVI FIRST, AND USUALLY BETTER.
Throw style out of the window and FFVI outdoes in sequel in almost every way. It offered a bigger, more varied and more logical gameworld with far more opportunity to exploration and far more to discover. FFVI managed to have a deep and complex story without the need to hit the gamer with ridiculous, intrusive cut scenes on a regular basis. FFVI was the fist game in the franchise to contain a truly deep gameplay mechanic, and a great deal of what you see cropping up in later editions can be traced back to this title.
Final Fantasy VI is easily the equal to any game that came after it, and deserves to be treated as such.