Technology roughly at the level of VII's - the original game, not any of the spin-offs.
A confident protag, that isn't either unrealistically brooding or annoyingly cheery. Roughly around the age of 25. Has his own REALISTIC problems.
A gigantic world map, where your character isn't just a little sprite moving around.
Airships, chocobos, and most of the recurring monsters, Moombas and Pupu included.
Espers, with storyline relevance. Ifrit, Shiva, Bahamut, Leviathan, Titan, Alexander and Diablos are mandatory.
Throwbacks to the previous games, but in moderation.
Some type of class system.
Give me some reason to explore, and make each individual town interesting. I'm not talking only side-quests and items, but background history and legit worldbuilding too.
sphere grids. lots and lots of sphere grids. a sphere grid designed differently and uniquely for each character for each job they can switch to. characters that would be better at a job can learn abilities than another might not be able to.
for example, a character better suited to be a white mage can learn curaja while a character better suited to be a thief can only learn up to cura. that character that's better suited to be a thief can learn bribe while the character better suited to be a knight can't. get it? each sphere grid would be unique to each character so nothing looks alike.
save points that don't replenish health and mp, and not being able to buy tents, elixirs and the like. INNS ARE AWESOME.