Puppet Master: Similar to how they are in FFXI specifically with how the puppet works. They can switch to different roles and equip gear to a limited extent. Giving us another pet class.
Beast Master: Also another pet class. They'd be able to "tame" various beasts across Eorzea. Weapon would likely be a whip. Unlike Summoner their main focus would be on their pet. Instead of an ally in combat they use their pet for the majority of their damage. Lot of pets management to succeed.
Beserker: A dual wielding barbarian. Likley 2 swords, or perhaps better yet 2 axes. They'd likely have abilities that allow them to attack ever so steady faster, and faster.
Blue Mage: A Mage tank. They absorb hits and reflect certain spells and abilities back at their enemies. Most of their abilities are about managing and using their enemies abilities against them.
Mystic Knight: Essentially the opposite of current red mage. Instead of being a magic users who sometimes melees. the Mystic Knight is a melee who also employs magic, weaving it into their attacks and enhancing their weapons with magical effects.