Right now i´m revisiting 6,7,8,9,10,10-2 and 12.
FFVI : Mech-wise theres not much to say it plays like any standard ATB, customization with the espers has some sort of deep. Plot & characters is well develop (minus optional characters) but the contribution of some characters to the story stops during the World of Ruin section. I finally can say without fear that Kefka>>>Sephiroth.... in the overrated category, i still fail to see why the westerns say Kefka is so well writen (and why they like him). I´m with the japanese players, he´s anooying.
FFVII : Something similar to VI but i personally found the materia system has more deep (custom wise), the optional characters have some development and backstory (though their contribution dont change the plot) and the story is as well done as in VI. Sephiroth suffers a bit of villan decay by the later parts of the game but not a deal breaker thing.
FFVIII : The mechanis are so beatiful to abuse and it leads to some fantastic results, like LV7 Zell dealing 9999 per attack !(most broken of all characters if used well). The plot is a bit week comparared to its predecesors but i still enjoyed it , i´m aware of the flaws though.
FFIX : This must be the one where i couldn´t stand (though it didn´t anger me) the battle system at least in the long run, even with the fastest setting its still so slow i think its the one of all 3D FF games that has the longes animation when it comes to perform certain actions and spells, moreover the trance system is a bit poorly implemented. When it comes to the plot its the same as with VI and VII its well writen though characters that are not name Zidane,Garnet or Vivi stops contributing or becomes irrelevant by the end of Disk2 or begining of Disck3.
FFX : This one is probably the one that i have the less problems and had most the pleasure with in my revisiting. I don´t have too much to add but the only thing that distubed me was the lenght of some cutscenes, special mention for those prior to boss fights.
FFX-2 : The plot this time is not as shiny as X but it was still enjoyable and i still don´t understand why many say its stupid (yes its not as good as X but still i never saw something stupid in this game). The Job system and leveling is pretty fun and has some interesting customization.
FFXII : The plot wasn´t as bad as i remembered i kinda like and appreciate it now (maybe because i like politic now), the battle system is very dinamic and customizable and is very well paced and license system is an interesting addition into the mix.
Final observations :
VI,VII,IX,X,XII have some bonus points for having some amount of thoughtful elements in their plot, each one well done in their own right, as to which did it better thats debatable but thats not something to discuss now. The gripe being mostly in the plot, most common being that the third act suffers from a bit of plot fatigue and prolongs far more than needed to reach the conclution.
Overall i enjoyed this experience and this was a long text , lol.