I'm really not liking wp-admin or similar folders' name structure.
IMHO during installation process (or via admin panel later) users should have a possibility to rename all WP folders and some crucial files like wp-login.php ie. from wp-admin to admin and wp-login.php to login.php or - even better - to something else.
This could improve security issues. Once WP code is seen , it's easy to learn what kind of CMS somebody uses = easier to hack a site.
Also this option would provide more flexibility to WP's customisation.