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

[Sandpark]

I totally agree with that, but I think there could be ways to play with the elemental system more without creating bloated situations like that or them being situational based on the fight. The mechanic exists, so I firmly believe we should use it somehow.

Something I played around with for fun was a dancer that could grant all allies either Enfire, Enwater, Enblizzard, Enthunder, Enaero, or Enstone with an action at random while also having an action that would drop the elemental defense of an enemy of the matching element. Everyone's doing Wind damage thanks to Enaero, you drop the opponent's wind resistance. Its functionally similar to just a defense drop on the target, but using the elemental system would help give it an identity.

But if only a hypothetical dancer would grant it, wouldn't that lead back to some parties wanting dancer over say some other support class?

Make it too weak or random and no would want dancer.
Make it too strong and other classes would start asking for nerfs or their own buffs.
And if it's just a flavor but the same thing as a defense drop then we already have that.

If the want is casters want Protect to be more than just cast it and forget it. Then it has to be a buff you can build up similar to Greased Lightning. I don't know how the rotation would work to accomplish that since Protect is a role action spell though.

Many fights have a DPS check, well this would be similar to a Healer Check. Say you get the spell version up to maximum Protect. In a circumstance a Primal ultimate skill would one shot the party. If Protect was maxed it could theoretically circumvent a group wide one shot just enough so no party wipe but just barely. In a party with more than one healer, it would take a stacked max protect from all healers to circumvent the group wide wipe.

Maybe you cast a low level defense boost protect 8%.
Then it requires a certain amount of hit points healed to keep it growing
At the next threshold it builds to 12%.
Next threshold it builds to 16%.
Next threshold it builds to 20%.

Change the icon to show 4 distinct sections, each section shows what threshold you are at. Recast required to upgrade the current spell level.
Cast it is Protect 1
When you hit second threshold, cast Protect 2
When you hit third threshold, cast Protect 3
When you hit fourth threshold, cast Protect 4

Or a simpler version where it requires more environmental awareness from the tanks, dps, and healers.

An area based effect similar to Summoners Shadowflare but way larger.

Members In the immediate vicinity of the caster grants a 20% defense boost
The further out you are the % is smaller, 15%, 10%, 5%.
There it would have to be recasted every 60 seconds.