Or introduce talent trees.

Conjurer would have the Black Mage tree and the White Mage tree.

Thaumaturge gets Red Mage and Time Mage. Or Time Mage and Summoner, as the latter might actually fit the lore.

Pugilist gets Monk and Thief.

Gladiator gets Warrior and Paladin.

Archer gets Ranger and Corsair.

Marauder gets Dark Knight and...something.

Lancer gets Dragoon and Pole Dancer.

Basically, you get to specialize in a tree, or take some from both. Spend enough points in a tree, and get a specialization bonus.