This new SP2 is not for the current game. It's for when immunities from most NMs are removed, but replaced with magic resistance so high that even Elemental Seal is ineffective.

What makes me wonder though, if the devs will give RDM spells or traits to affect aoe melee attacks like those from Iron Giants. If RDM (and RDM alone) would be able to slow down those attacks or even paralyze the occasional JA, it would revitalize the job's usefullness.