Discussion on how good Plenary Indulgence is now aside, a lot of classes get abilities that aren't that great or amazing for "capstone" abilities. I mean, Scholar got Dissipation in Heavensward, the worst cooldown among all three healers. And now they have Fey Union, which isn't that spectacular either. Machinists got Flamethrower, which is amazing visually but to my understanding very weak. Assize was arguably a stronger ability than Tetra. It's weird to want it to be super amazing just because it's the level 70 ability, and even weirder to act like this is something unique to WHM.