One of the problems that a namespace try to resolve in Tiki is to have multiuser sites, where users can have his own content. If a user can create a page ))AboutThisSite(( could be confused with the site one, so in multiuser systems is a delicate thing enable group of users to create wiki pages.
A solution for this could be to have namespaces and all content created by an user to be enclosed in a user dependant name, i.e. gmuslera/MyWikiPage or gmuslera-MyWikiPage, and I had written about that somewhere else.
What I propose here takes another point of view. Already exist the possibility for a user to have ))UserPageusername((, IF the user have the possibility to create pages, but that opens the possibility of creating page names that could cause trouble. But what if we have a permission for "creating user page"? Then if the user can create his user page, and no for creating wiki pages in general, the user can have his page, they will not be confused with the system ones, and will not have side effects in general.
But more than this, what about more object types? A normal web application are blogs, but also could have problems that normal user can create blogs, any amount of them, specially in multiuser systems. But if we can have (in the same way than the wiki) Userblogusername, and a permission that enable the user to have his own blog, we can have each user (in a group) with a blog, and the name in listings will not be also mistaken with system blogs (could be nice to have urls that say that the browser is accessing some users blog instead of some number, but that is discussed somewhere else too).
The same could be useful for image and file galleries and maybe more object kinds. So, what is needed to do that? Well, first an agreement that this is a good idea or not . But after this, a new set of permissions should be created (tiki_p_create_user_page, tiki_p_create_user_blog, etc), permission checking for the creation/editing of his UserPage for wiki pages, or one and just one as his personal blog (with his name as description, to put something fix), and things like that for the other content types, and modify the preferences pages to enable the creation of his wiki page, blog, etc, probably checking first that the user have enabled the right permissions.