Fuck it, I may get in trouble for this -- The Cursing Immunity system will be changing slightly (possibly in time for Ascendancy, but more than likely in a following patch). There will be a 'soft' form of Immunity, dubbed "Hexproof", replacing Curse Immunity as we currently know it. Curse Immunity in it's current state will still exist, but it won't be rollable on maps. I don't know exactly how GGG intends to use Curse Immunity after this change goes live, but Curse Immunity will still function as un-bypassable mod for Flasks & PVP. It may or may not still appear on monsters when this change goes live -- I don't have those details specifically and they likely haven't been worked out yet.
<br /> Along with these changes a unique I designed call "Cospri's Will" will be introduced into the live game at (likely) the same time allowing you to bypass the Hexproof mod which will be replacing the Curse Immunity map mod. My unique will allow you to bypass Hexproof, but not Curse Immunity when it still appears on enemies. I cannot say how rare Curse Immunity will be, if any mobs will have Curse Immunity, or if some will inherently have it at the time these changes go live. However, Curse Immunity will remain in the game (in some form) as a un-bypass-able mod on flasks for PVP purposes and for mobs when GGG feels necessary for balancing purposes.
<br /> In short my unique will allow you to bypass Hexproof, which is replacing the Immunity map mod, but without my unique you will not be able to Curse a mob with the Hexproof or in a Hexproof map or a Curse Immune mob.
<br /> This information in subject to change and is based off the correspondences I've had with Nick from GGG. I cannot and will not guarantee this system as I've described it goes live as GGG may make changes as they feel necessary prior to going live.
Apologies in advance to GGG if I shouldn't have disclosed this.