Everything since the PS1 generation?

FF10
The best of the bunch, in all honesty if it wasn't for the subsequent entries I would probably just count it as a weaker title rather than part of the disappointing half of the series.

FF11
Argue all you want about how it is a game deserving if a numbered FF entry but it still should have been called FFOnline. I think FF Tactics is the best game in the series, and it was still correct to label it as a spin-off title.

FF12
The game to me speaks of horrible conceptual design decisions with fantastic implementation, which makes me disappointed with how good it could have been.
- Combat was exceedingly simple and easy (illustrated by the fact that a 10 line AI can beat the entire game for you easily.).
- The story took itself way to seriously for how bland and predictable it was (once again, simple story isn't bad, but it shouldn't seem like the developers think they are writing the next Game of Thrones entry).
- The character set up was weak, you couldn't see the grid to plan your characters, and it was mostly irrelevant because you just learned everything on everyone. Had they had some sort of way to limit the skills/spells you could have equipped at one time the set up aspect would have actually required some thought.

FF13
Almost the exact opposite problem of FF12, they started with some interesting concepts as delivered extremely poorly on them. If you make a game that strips out exploration to focus heavily on combat and story you better damn well make sure that you do a good job on both of those things. With some better writing and a slower and more involved battle system the linearity of the game would be working for it not against it.

FF14
See FF11.