Originally Posted by
Wilfire
One of the key points of Warcraft mythos is that your appearance matches your soul. When Sargeras and Neltharion became evil, their bodies became more jagged and demonic. AU Gul'dan's form, despite him getting amped up on Fel and cured of his deformity, still became as gnarled and crooked as his soul. Azshara's beauty became gorgonic.
On the other hand we have pretty boy Anduin being a literal beacon of holy Light.
What Kyrians do is induce complete ego death. Pelagos was brainwashed to such a hardcore degree that he rejected his old appearance which was the true representation of his soul. Even Uther, despite being all about the greater good, wasn't able to be brainwashed to that extent.
All Shadowlands afterlives are torturous and horrifying but being brainwashed until you willingly say "fuck you" to your old self and become someone else entirely... well, I'm not sure being tortured in the Maw while remaining your true self is that much worse. Sylvanas is completely right that the Shadowlands should be broken.