The Hardest Part Of Peer Feedback: Giving Them Constructive Criticism
When the feedback prompt asks you for what your peer can improve on, it is not asking you what your peer is doing poorly. If you see your peer doing something toxic/negative, you should give them that feedback immediately. Don't wait 6-12 months until performance review season to drop this giant ball on them.
The real question behind this prompt is: "How can your peer expand their scope?