What is it to add another? That being said most Faunus have excellent night vision anyways. There'd really be nothing special about his other than colour.

It's a little difficult though considering a crow's most outstanding trait is actually their intelligence, not a physical trait.

EDIT: You say we have two many "eye" type Faunus but we literally have just one whose eyes are a trait that stands out and that's the snake. That said, our snake should have some scales or fangs in my opinion, but neither of those key words seem to show up, so yeah.