Calia, as she currently stands, is antithetical the very identity of the Forsaken. She can be beloved by them and all that, but it doesn’t change the fact that they have nothing in common.
If we are to be saddled with her, I would want her to learn firsthand of just how out of touch she is. The Forsaken have been without her for years, carved out their own place, own identity. They aren’t some freshly raised corpses dealing with the trauma of being risen like Delaryn, they’ve been there and done that. Without her.
Let that be a driving factor in how Calia tries to deal with them, trying to impose compassion only to find them cackling as they test out a new strain of blight, wallowing in self-pity, blaming the living, or outright plotting murder. Let her fail at leading them because of her lack of understanding, turn that bright light into a darkness. Show that even when reborn with the light she cannot resist the dulling of her emotions as an undead and slowly becomes one of them, much to Anduin and Jaina’s horror.
A Dark Lady 2.0 if you will.