I would like to see the FF8 system where every character can equip one summon to add to his powers. If he wants melee power while he is mage he can use Ifrit for example.

Summons has skill trees as well so you can use those abilities from the summon if you unlock them. FF12 system is really nice one to have. with Summon added to your character you can become any type you like. Atma system in FF11 but with summon instead .

and PLEASE SE if you doing combat animation try to make it really heavy and cool, the sound of the attacks and the feeling of the hits really important, make it feel like real fighting. sound effects really has huge impact of how we like to use the character , with great animation as well.

classic jobs in FF has also tree skills will be great to have with some sub trees from other jobs as well.