After FF6, the series really lost its 'fantasy' feel. The worlds just quit being unique and standalone.
FF7's story, when you think about it, is just a repeat of 5 (using the Earth's energy up, just like the crystals) and 6......but the main character is much harder to like.
FF8 is just the evil sorceress thing again. I didn't play any after that.

What I really liked about FF6 was how they managed to incorporate THAT world's history into the game very well. The sidestories were very well done as well. Cyan's dream was amazing. I still remember the first time I came across it with marvel. The sunken castle was completely unexpected. The flavor of the world (sort of like a mix between fantasy and the victorian age) was really special. The only thing the game lacks is a sequel. FFX2? How about FF6-2! My hope is that square will use its portables to get back to its roots someday.

Oh yeah, I would never have seen the WoR coming. That caught me completely offguard. Biggest surprise in a game ever, right next to MGS2.