This latest Final Fantasy: The 4 Heroes of Light trailer shows off the "Crown System" that allows you to assign jobs to your 4 heroes throughout their quest.
Crowns enable you to take on different jobs. Tired of being a White Mage? Then simply switch to another crown and presto, you become a Bandit, or Paladin, or Alchemist! Each job grants unique abilities that you can set up in the Abilities menu and use in battle.
You must set up crown abilities and magic book spells with the Abilities menu if you want to use them in battle. First select an empty ability panel and then choose the spell or ability you wish to set up. To replace a spell or ability, simply select the spell or ability you want to replace and then choose a new one to put in that panel. To delete a spell or ability, select a blank panel as the replacement.
You can change crowns whenever you like. When you do, the abilities and spells that you had previously set up will all be removed, so don’t forget to reconfigure them in the Abilities menu.1