I would want a Dark Corvus, Riolet, or C Pavel skin.

Dark Corvus as he can get facial expressions, maybe lose some armor. I see three possible outcome for his personality and revoicing lines. One he is still aligned with the goddess and sounds less depressed and dejected. Two, he does a successful Arby (in he kills the goddess, maybe he also kills the archdemon) he could be the alt timeline cause of Cidonia's spirit imbalance. Three, he becomes a generic berserker and sound more angry.

Riolet-- Emperor of Cidonia, the skin is simple. He become more noble in Appearance.

C Pavel -- I don't know how to improve his appearance, but I would enjoy another skin. If I had to guess, more of an assassin appearance and "black ops" title or the like.