I would like to propose the idea of having a built-in way to support hierarchical content from within keystone. This is a common feature in other CMS's. This concept can be used to build navigation as well as listing pages.
Right now this ends up being a bespoke feature in almost every site I work on.
Some considerations include:
Not all content is hierarchical in nature.
Navigation isn't always built using the site heirarchy. (i.e. blog articles may be children of a blog index page, but their navigation follows a /:year/:month/:day/:slug format).
Fast lookups of children, parents (for breadcrumbs), siblings using something like mongoose-nested-set
There may need to be multiple root hierarchies.