I talked a bit on this on Wiki_in_Multiuser_Portals_gmuslera and TikiNames_gmuslera, and tex with NonStrictHierarchicalNameSpaces plus some was talked on the mailing list.
What I propose here is to have system for names in wiki pages, one that can avoid conflicts, could be somewhat intuitive to use and understand for users and administrators, and probably could make Tiki more scalable. Is to use something like in the domain name system, with names like subdomain.domain.com? well here could be something like page.category. or page.username. or even page.category.username. (for the cases that the user could have his own particular categories). The same goes if the order is in the other direction, like .category.page, I just choosed between one of the alternatives for this explanation.
How it could be used?
When a user creates a page, i.e. a MixedCaseWord, if its out of context (i.e. with the quickedit module or playing with the URL) it will be in fact MixedCaseWord.username. . If he want to create a top level page, the name should end with a ".". In the other hand, if a page is created following the "?" link of a wiki word, it belongs to the same "domain" that the original page (if was a page from a category, then the created page belongs to the same category, and the same applies if it was the page of an user.
There are pages that are created with a "full path" by default, like the site homepage (that belongs to ".", and the same happens for the ones created from it), and the user homepage (that belongs to .username.). For categories, maybe the quickedit dialog could be used to initialize a category with a page creating something like InitialPage.mycategory. and from there start creating and linking content, or the category creation dialog could ask for an initial page, or putting wiki pages inside a category renames then to add the .category. suffix.
With this scheme of things, how the normal operation of the system goes? When a user put a MixedCaseWord in one of his pages, in fact is referring to MixedCaseWord.username. but if he puts MixedCaseWord. he is talking about the top level MixedCaseWord page, and the same goes if he adds the category name with a dot at the end.
There are things that Tiki could do for making things easier like if the page can't be found at the user level try to see if one exist at the top level and link it instead (could be dangerous if the user really wanted to create a new page) or if something like MyPage.mycategory is used (without "." at the end) assume that there are a dot at the end (things could get complicated if user categories are enabled), or even if a page is referred as .wordone.wordtwo, and there is no user nor category named wordone, then assume that this is the full name of a top level page. In fact, if there will be no subcategories or user categories (thing that could be wanted in a future, anyway), then just one dot is needed, and that sometimes, and could have pages like username.page and category.page and .toplevelpage as full names.
See also: TikiPageGroups.