1000 HP/6 turns is actually the same as Ithaqua's heal, and then the passive would pull Gryla ahead of Ithaqua. Whether that says more about Ithaqua herself or about the general power creep...

Hell, speaking of Ithaqua, I think overall, Gryla's in the same tier as her, arguably better than her within that tier. (I also don't think all that highly of the rest of Ithaqua's skills). Thanks to power creep, that means Gryla's an event kamihime at roughly the powerlevel of a gacha SR from this January (so ~11 months older than Gryla).

Thanks powercreep for allowing event kamihime to finally start including healers! (starting with Ashtar in end of September/start of October)
(starting with Phoebe in beginning of September if we count single target heals, despite being attack type, cause water continues to be water)