As a person who started on the first Final Fantasy that was on the NES here in the states, I have to say, FFX was when it started to slip for me. It was still a good game, but the new style and overall themes started to turn me off. Then I played FFXI online, and after about 3 months, I cancelled my subscription and never went back. Then I begrudgingly tried FFXII, and actually found Fran so cute that I kept playing through it, though the game never really drew me in. THEN, I played FFXIII, and that was the lid on the coffin. I was so turned off by the way the story was delivered, and how far they took FFX's style that I didn't even come close to considering FFXIII-2.
And THEN I played Xenoblade Chronicles, and that drove the final nail into the coffin for FF for me. Cool story, bro? I know, but having played FF since the NES, I miss the classic style, the more mythological and "steam powered" days of lore. Xenoblade Chronicles took me back to the older FF style, and now I'm all over Monolith Soft's nuts, lol







