I actually wasn’t aware of that. Learn something new each day. And, personally, that kinda makes it worse.
That means Light’s Wrath had the potential to work in a duality nature, but still didn’t.
I pretty much agree with what Irenaus said. Whether or not Light’s Wrath could be corrupted back to a shadowy state (it’s implied it could be in the Artifact history) is irrelevant.
Discipline is described as such in the Legion re-imaging of the spec:
Some priests pride themselves on pragmatism. They understand that light casts a shadow, that darkness is defined by light, and that true discipline stems from one’s ability to balance these opposing powers in services of a greater cause. While these priests possess many holy virtues to aid their allies, they also dabble in the dark arts to debilitate their enemies—always exercising immense discipline to keep themselves away from the brink of insanity. Many would say the ends justify the means; scriptures both virtuous and vile should be studied and understood to protect the congregation.
But I don’t see that mirrored in Light’s Wrath at all. Nor Netherlight.
In Legion, the Priest Class Hall put on a bit of eyeliner, dyed their hair black, and said “How do you do fellow Shadow Priests?” without actually putting effort in to it.