I think one thing I always liked about final fantasy was the way we always had to rely on items or magic to cure what ails us. I would like to see some more longer lasting status effects that required a mage/item to cure - such as blindness, slow, sleep, sadness, poison, etc. It would be nice to buy items to use out on the field like in the old days.

I also don't like how the HP/MP restore instantly upon resting. I know this is good for MMORPGs as it is a staple, but for a final fantasy feel I would like to opt for more HP, take less damage per mob that builds up over time, and relying on potions/cure spells to restore. Ether for HP or drain. Magic spells should also do more damage when used properly.