You are on a roll with the thread creation WK.

I think each game is overrated in it's own way. I'll run down a few and my thoughts.

FF7
The first game everyone's mind jumps to when someone mentions 'overrated' and 'final fantasy', either to label it or defend it. While there is no denying it has it's extreme fans I think that at this point the hate on it for being overrated is greater than the actual overrating itself. Personaly I don't think FF7 was anything more than FF6 with better graphics, but I think the 2D->3D leap was significant enough that this made a profound difference in the overall package. And even though the game wasn't the miracle title it is sometimes made out to be you are a fool to discount the profound effect it made on the JRPG, and to lesser extent gaming, landscape.

FF9
One of the worst offenders on my list. FF9 is an excellent game. However it seems like people's disdain for FF7&8 has led them to over inflate FF9s worth to compensate. In particular I feel this game has some major problems with pacing, and everyone who is a fan of it has managed to convince themselves that there is nothing wrong with the battles. I don't have a problem with them in the least, but I don't see how they could appeal to anyone who wasn't determined to like the game from the outset.

FF12
I feel this game is both overrated and fairly rated. What I mean is, I feel the game is overrated by the people who like it. However it is a fairly divisive entry, with a large counterbalancing negative opinion. If you average the two out it comes out fairly fair.

My personal opinion is they did an outstanding job putting a game together built around poor game design and plot decisions. The overall game experience being decent, but I will viciously rip apart just about every part of it when analysed.

EDIT:

FF13
This is more a reaction to critical response than fan response. A whole bunch of review sites gave this game extremely high scores, whereas others decided to give it ridiculously low scores. It seems like game reviewers were scared to give this game a less than superb score because it was a major release, and if they disliked it strongly enough to buck the trend they felt they needed to give it a score intended to shock instead of evaluate. So I think this game isn't getting a fair shake either way, but this thread is about the over-rating part.