https://secure.phabricator.com/settings/panel/home/ provides a UI for users to customize their homepage. It is very useful!
Now, could we get exactly the same UI as a tool for administrators to change the homepage that anonymous an registered users get by default?
T4103 also talks about customizing homepages, but that implementation is a lot more complex. Here the main elements are in place already: the settings/panel/home UI, admin tools, admin permissions.