Hmmm I've never animated wings But I think the motion looks fine! Maybe it might help if you look up wing diagrams, the tops of the wings look like there's only the 1 joint in the middle but from the back there should be 2 joint so you'd have more of a zigzag Then you could emphasize the wings opening by starting them folded And maybe stretch them more in the last frame (Sorry if this is confusing or unhelpful I'm terrible at explaining ;v;)