In reply to Mark Skeet.

@Mark We can't fit everything into a single release. We're adding new building blocks with each release. The scheduling of changes in the Customizer in 4.9 can be a stepping stone to being able to schedule content changes. The infrastructure for drafting and scheduling was actually added for changesets in 4.7, but there was no UI until now. With the Customize Posts feature plugin you can already schedule changes to posts and pages, even multiple posts and pages at a time, while previewing how a change to a post looks wherever it may appear on a site (homepage, category page, search results, singular template, etc). The UI from Customize Posts won't be merged into core, but the underling infrastructure I expect will be merged. As we move forward with integrating Gutenberg with customization, you should start to see publishing of scheduled changes. Whether or not you are in the “Customizer” interface, it could still leverage the changeset scheduling infrastructure that is now in core.