Ummh, I´m thinking on it. Magic with a very strategic porpuse, it should be able to alter the reality. Teleportation, changing the position of partners, alteration of the enmity, being able to alter the strength and weakness of himself his party and even his enemies. A class which don´t need to fight or heal to be usefull, a class suit for strategy fighting. Red mage will watch every aspect of the battle and use a great variety of spells to change the odds. Making cure regen MP but consume HP when used, use some old spells like relfect and debuffs, changing magical damage for physical. It should have weaks stats and some limitations of course, and most of his spells have a good and bad effect.
A full strategy job, the kind of person who can overcome imposible situations using his mind and his sodiers, partenes and friends.
Red Magic should have a lot of diverse spells with different uses and a bad red mage would kill his party, while a good one will make a 8 men unstoppable army.
This just one idea, I´m still thinking.