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.

[Lemuria]

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.

How soon we all forget. At the launch of XIV, there were two separate spells. Protect and Shell. It was only when it was remade into A Realm Reborn that we lost Shell and it became a trait added onto Protect. What's more, Protect and Shell had a far more dramatic increase in defense in their original forms, reducing damage by a very noticeable margin.

Mind you, these were also the days where Conjurer also had all of the elemental spells too. Banish was in the game too, but as a Thaumaturge spell.

[bass9020]

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.

At the time it was ok though since we only had 2 healers. AND Scholar did have a magic defense boost in the form of Eos with the Scholar ability Fey Covenant. But of course it makes people have to think and thinking is bad!!! Then with Astrologian added in things got more complicated (don't know why but as usual things got simpler), so instead of coming up with a way for Astrologian to protect against magic they just gave all 3 healers Proshell. So creative! So unique!