At the moment, all the site's pages are in a single "bucket". As such, all the site's URLs are very simple: https://<domain>/<slug>
This situation creates a few major issues:
  1. It hurts SEO (a lot).
  2. It makes it hard to manage if you have a lot of pages.
  3. You create any structure on the client's side (e.g. "posts", "services", etc.).
  4. You can't create several pages with the same slug, but in different locations.
I have two ideas as per implementation:
  1. Use the current "custom asset" feature, but generate full URLs for the assets (currently they are being "flattened").
  2. Recommended: allow the creation of folders (either logical or physical) on the "pages" interface.
Overall, I don't think it is a difficult feature to implement, given that there's already a URL Rewrite option.