I think you could improve the wordpress comments in the next version, respectively comment_form(),
2. Remove install.css from wp-comments-post.php, nothing on frontend should be in wp-admin
3. Allow users to set more options in admin backend following the current scheme:
Comment author must fill out name and e-mail (already there)
Comment author must fill out name
4. Allow users to remove fields (website and mail) completely via admin backend
Just throwing this out here, I think there is room for improvement to make it more user-friendly.