If we have to keep PI as yet another flippin' heal, then it should stay as-is. All PI is right now is another OGCD heal so we can spare a GCD spell like Cure I. Making it AoE makes its use cases less clear, since if it procs it will most likely be on the MT, and if it heals in an AoE then only the MT and maybe a few melee DPS will benefit most of the time. It's not reliable enough to suffice as an instant Medica, which would be its primary purpose if that was the case. May as well keep it as-is and up the proc rate slightly and/or increase the stack timer (preferably permanently or at least 1 minute).

If I had my little way it'd be the utility spell a lot of WHM have been asking for for ages. SCH already has AST encroaching on its turf with mitigation and AST already has party buffs covered, so WHM should get something unique but still very "healer" in feeling.