Aside from the very obvious need for it's proc rate and way to proc needing to be changed (you need more control with something like this, I'm regularly popping indulgence on full health tanks).

It needs to not have a duration to it. It needs to have a static buff.

And one Confession should work as an AOE heal targetted around the player who has it.

For example, the tank has confessions. Using plenary on him should heal everyone around him for a certain amount.