My opinion on most of the earlier franchise has been relatively static, but starting with FF7 my opinions have shifted around fairly heavily.

When FF7 launched, it made me want a PS1, and for the longest time it was my favorite game in the franchise. Somewhere along the way my opinion shifted, however, and I became fairly certain the game was an overrated piece of crap. A few years ago, I reassessed the game again and now find it to be one of the strongest entries in the series.

Conversely, I was pretty quick to lambast FF8 when it came out. I hated the story and virtually all of the mechanics, but, playing it recently, I found myself enjoying the customization the game presents and think well enough of the game now. The story is still bunk, though. ._.

FFX, and I'm far from alone here it seems, I adored when it came out. However, after getting ahold of International a few years back and attempting to play through it again, I felt the game was far too restrictive and simply drug me along by the ear. This was especially compounded by my inability to tolerate either Yuna OR Tidus, both of whom, to my unfortunate realization, receive a lot of camera time. Overall, my opinion of the game is a LOT lower now than it was originally, and it is (easily) one of my least favorite entries in the franchise.

FFXII. My undying hatred of MMORPG-ish games cannot be understated, and that's always how this game felt to me. I was actually given a copy not too long after it came out and threw it into my closet somewhere after playing it for about an hour. Years later, a friend of mine got me to play it again, and to give it a fair shot, and I actually think pretty highly of the game now. I still don't especially enjoy how combat is dealt with, and I utterly HAAAAATE semi-random loot treasure boxes, but I love most other elements in the game.

FFXIII was the last one I had a major shift on, and it was actually for the better. I originally couldn't stand anything about the title, from the characters to the combat, but my opinion has largely cooled since the game's release. I don't mind Lightning as much as I did initially, and I like Sazh as well, but probably the biggest change was my outlook on the combat system. I don't think it is especially good, but I find it interesting enough; it is certainly unconventional.