Final Fantasy.
First gameplay wise - go to a more traditional turn based strategy combat mechanic. Recent attempts to make it something different have utterly failed, particularly in FF XIII, rather go with something a bit simpler that allows the player to feel like they are playing the game.
Second gameplay issue, reduce the combat. The more combat you have the better the combat system has to be in order for it to avoid feeling like a chore that gets in the way of getting to the good bits. The series has never been noted for its great combat, reducing it will help the games pacing.
Third, graphics. Reduce the budget to them. The last great Final Fantasy was VII, and it was a step back from VI, these are the games you keep hearing people request get re-done in a modern style. They aren't graphical powerhouses. Strong aesthetics can be a good investment, but cut the emphasis on pixel power.
Fourth, setting. Make it fun to explore. That was part of what made the SNES games so much fun, the fact that you could see this whole world to explore. Final Fantasy at its strongest is a game all about its settings, which is why removing the shops in XIII removed so much from the game. Make sure the setting is good and everything else will fall into place.
Fifth, Villain. Stop trying to remake Sephiroth. He was good for one game, not every game.
Sixth, Player Characters. If Bioware has taught us anything, it is that it is easier to make interesting non-humans than it is to make interesting humans. Learn from that and give us more non-humans, because again, Final Fantasy is a series about settings so if you can make your allies part of building that setting, it is all going to work out for the better.
