The existence of XWikiUsers objects should not be limited to the XWiki-space

The introduction of nested spaces / pages has been a blessing for more complex (eg. object-oriented) applications that use XWiki. We're able to implement - those complex - structures in our applications using the nested nested spaces / pages that XWiki provides and could get rid of the ambiguous 'parent'-relationships we used to circumvent the limitations of XWiki's 'flat' Space-Document structure.
Unfortunately, we're not able to use the new 'nested spaces / pages' features in the management of XWikiUsers. Objects of the XWikiUsers-class can - at least for users that need to log in with 'basic authentication' - only be created in the XWiki-space. This is 'hard coded' in the authenticator (https://github.com/xwiki/xwiki-platform/blob/master/xwiki-platform-core/xwiki-platform-oldcore/src/main/java/com/xpn/xwiki/user/impl/xwiki/XWikiAuthServiceImpl.java). Whenever someone - a guest or a logged in user - views a user's profile, the breadcrumb points to the XWiki-space as it's parent. Most users / guests have no interest in the XWiki-space and / or are denied access to most pages in the XWiki-space. So clicking on the XWiki-space breadcrumb leads them nowhere. Our previous code enabled us to set the parent of XWikiUsers-objects - by means of a 'document save listener' - to the / a User Directory we defined ourselves. This seems to be impossible in the new 'nested spaces / pages' concept of XWiki. So whenever someone views a XWikiUsers object, the parent breadcrumb leads them to the XWiki-space and effectively to the Information-message that states there's nothing to view for common users.
Sorry for this extensive explanation, but we wonder why the creation and use of XWikiUsers objects are confined ('hard coded') to the XWiki-space? With the introduction of nested spaces / pages we're unable to set the parent of XWikiUsers objects to - eg. - a UserDirectory page. The breadcrumb therefor leads all users to the XWiki space (and they generally have no rights to view pages in that space). From a usability perspective, this is a bad practice. Why not query for all XWikiUsers-objects (in whatever space(s) they are stored) when authenticating a user? That would enable far more flexibility in XWikiUsers management.