It is only a proposal:
http://meta.wikimedia.org/wiki/Efficiency
look at
http://meta.wikimedia.org/wiki/Non-Articles/Articles
and
http://meta.wikimedia.org/wiki/Wikipedia_article_depth
if you change a part of definition - Non-Article/Article -> Article/Non-Article ... some wikis works well without thousands of userpages (facebook), meta-pages (subpages of AfD etc), filepages (we have Wikimedia Commons ;) and others.
best regards
przykuta