Add Shell, and don't make it stackable with protect.

[Bacent]

Isn't that what Protect is in this game?
Shell in FF series - Increases Magic defense. (There's another small alteration in FF6 but still the same thing.)
Protect in FF series - Generally halves all physical damage dealt to the target.
Protect in XIV - Increases the physical and magic defense of target and all party members nearby target.

They basically merged Shell into Protect.
Actually they made Protect, Proshell.

Don't forget at the launch of XIV only White Mage had Protect with Proshell, any other healer had to make due with only a physical defensive boost instead.