Well I have to say IX. The story and characters are amazing. That said, there are some gameplay issues:
-Combat has a few kinks.
-Some characters are much more useful than others.
-Lots of grinding in order to master abilities.
-Too much of the extra content is mixed-up with the chocobo mini-game.
-The final boss seemingly comes out of nowhere (Not really a gameplay issue but still). There are alot of theories surrounding where he comes from but nothing is really spelled out.
-Card game is harder to learn and less useful than in VIII (although the rules don't randomly change on you).
That said, the story is solid and the characters are entertaining and well developed. Its also has a decent sense of humor too.
Edit: Oh and its the last Final Fantasy game to have an actual overworld.
-Combat has a few kinks.
-Some characters are much more useful than others.
-Lots of grinding in order to master abilities.
-Too much of the extra content is mixed-up with the chocobo mini-game.
-The final boss seemingly comes out of nowhere (Not really a gameplay issue but still). There are alot of theories surrounding where he comes from but nothing is really spelled out.
-Card game is harder to learn and less useful than in VIII (although the rules don't randomly change on you).
That said, the story is solid and the characters are entertaining and well developed. Its also has a decent sense of humor too.
Edit: Oh and its the last Final Fantasy game to have an actual overworld.