This spell could actually prove to be more dangerous than helpful in some cases. If your allies are always getting back up at 1 Hit Point, then, 1.) they're more likely to be targeted, which means that 2.) they're far more prone to permanently dying, as it's far easier to reduce their Hit Points to the negative value of their Hit Point maximums (i.e. a Wizard with a 25 Hit Point maximum rises back up with 1 Hit Point, only to take 26 damage, killing them instantly rather than knocking them unconscious).

Paladin getting it at level 13 it is less risky than cleric at 7. Good point though, high level aoe or melee hits could be deadly (especially autocrits)