A perfect FF, eh? Difficult, but I'll see what I can come up with here...

  • Class/Job system of course, that was one of the best things they ever put into the games. I also liked job promotions, but perhaps tweak it even further, and give each job multiple promotions, for example, a Knight could advance to a Paladin OR a Dark Knight, allowing for futher cutomization of your party. Not to say let any character be any class as good as any other. Based on each character's individual stat growth, make it fairly obvious who should be using what sorts of classes.
  • Abilties from Weapons, pretty much IX's sytem, gaining AP to learn abilities attached to weapons. These would be more general abilties that you can use regardless of Class.
  • Materia (or equivalent) for non command abilities. Basically equippable passive abilities, again to allow for freedom of customization.
  • Abilities from Class, pretty much like they did in X-2, for class specific abilities.
  • Weapon Customization, pretty much like in X, perhaps with a side of XIII customization to directly increase stats instead of just adding abilities.
  • Either ATB or full Turn base, as long as it isn't some god awful action game hybrid experiment.
  • Limit Trance? Thinking about ultimate attacks, I came up with an idea that kinda combines Trances with Limits. Basically, a Limit gauge, when it fills, you go into a character (not class) specific Trance (or equivalent), and once you do certain things during that Trance, you'd be able to use your ultimate attack. For example, a character who's obviously supposed to be using mage classes would have to use a certain number of spells or something before the trance wore off to use an Ultimate attack. This may or may not work, if I had to choose between one or the other, I'd say go with Limit/Overdrive again, but I kinda liked the idea of having both in some way.
  • Story obviously. I don't care how good a game plays, if the story blows, the game blows.
All I got for now, I'll give more though to it later.