Cure IV? Seems fairly obvious, but all the same. As far as what utility it could bring to the kit, I seem to recall someone suggesting it having an auto-regen application, which would save on casting times at the very least.

Going off of Kuribou some more, maybe a skill similar to Reverse? Turning what are normally healing spells into powerful attacks? Though given we've already got Cleric Stance for general offensive options, perhaps make it something more like an OGCD Ability, keeping potency affected by Mind rather than Intelligence, enabling some timely DPS on the fly without having to switch to Cleric?

All I've got off the top of my head.