Re: about the member theme folder
it’s all about consolidation and managment. i think WP not only a blogware but also a CMS. so it will forge alot of MODULES just like Drupal does.BuddyPress is one of them. if all modules put it’s theme a diffrent folder, it’s not an error, just somewhat chaos for developers/site admin.
i DO know buddypress user theme cannot used by WP blog.