dtgreene: I actually found FF6 to be when the series started to decline, though it at least gets points for its female main character and its non-linear later part.
Vinry36: May I know why you think this way? Did Square Enix change some elements from its previous FF games in the later games or something? Or is the stories of the later games just aren't as engaging?
There was definitely a big change in the series at this point. In fact, I believe that the director changed between FF5 and FF6, with FF6's director going for a more cinematic experience, rather than the more gameplay-focused experiences of the early titles. Among the consequences of this is that you're spending a lot more time watching cutscenes and a lot less time actually playing the game.
One significant change is that the classes/jobs that were a huge element of the series, and perhaps defined the feel of the series, disappeared with FF6. Classes like white and black mage, for example, are gone at this point in the series.
Also, FF5 has this wonderful job system, where you can give a character a job (what other games typically call a class, so like Knight or White Mage), learn some of the job's abilities, change the character's job, and then equip one of those abilities on the other job. For example, by changing a black mage into a knight, you can equip Black Magic on the knight and get a knight that can cast black magic. There are tons of combinations, some of which interact in interesting ways, but you still can't make a character who is capable of doing everything at once.
FF6, by contrast, throws that away rather than building on it. Characters have unique abilities, but everyone can learn every standard spell, have all of them available at once, and in doing so you know longer have trade-offs when choosing which roles characters need to fill; everyone can fill every magic-oriented role at once, without sacrificing fighting ability.
FF5 actually builds off earlier games in the series. FF1 has character classes for your characters, but you can't just change them. FF3 is the first game in the series to use the term "job", and you can change them, but can't equip abilities from other jobs. FF4 is a bit of a step down, giving each character a fixed class, but forcing party changes as the plot progesses (instead of letting you choose your party). FF2 is a bit of an outlier, but it still has the feel of character classes, particularly with one of the early characters being a white mage. (Though, to be truthful, FF2 feels like it could have been SaGa 0, with its unorthodox approach to character growth. No levels; instead, your actions during combat dictate stat growth.)