Sometimes, A link to a special page required by a plugin or theme is required to be hardcoded. An example for this is a link to a cart/help/faq/tos page etc.
Publicly distributed plugins and themes each have their own implementation for this problem, adding a bit of confusion to the end user. And when developing sites for private clients, I ofter find myself hard-coding page id's, which is obviously not optimal.
Here is my suggestion:
register_page_type('slug', 'Title', 'Description', 'callback_if_doesnt_exist');
This will allow a plugin/theme to declare it used the 'tos' page type for example, and an optional callback if the page does not exist, allowing for it to be created.
page-[type].phpin template loading hierarchy (after regular page and before custom template)
The backend of this would be similar to the navigation menu mapping option, where users can select the page for each page type from a dropdown.
I would love to contribute this feature to the core if the idea gets approved.