Distain, the thing you're failing to realize, is that there was no redemption for Kadaj in the end. He tried to kill Cloud one last time but completely lost all energy and fell. Cloud showed some compassion and caught him, but in the end Kadaj still called out to mother as though she was taking him home. Then the rain turned him back into the Lifestream that he was. There was no redemption scene for Kadaj.