Even though though the new interface makes no mention of the Guest account, it is still possible to enable it using the computer Management Console. However, the account still does not show up at the logon screen and there are reports that even after fiddling around with the user settings, the account doesn’t work correctly anyway, often refusing to allow people to sign in or behaving erratically once signed in.
The obvious workaround is to simply create a new local account with restricted privileges (called “Visitor” or something similar, since “Guest” still technically exists), but even then, there is no way in the new Windows interface to create a local account that isn’t tied to a Microsoft account.
It is possible to create such an account using the Management Console, but at this point it’s fairly obvious that Microsoft don’t want you signing in to your computer without a Microsoft account.
I’ll be keeping an eye out for an update on this from Microsoft. There is a substantial base of users out there that make use of the Guest account, and to remove it without notice is definitely interesting…