(This is a minor issue, but presumably still relevant, given that the new experience intends to work well with password managers.)
Upon being prompted for my email address, if I tell 1Password to auto-fill the form, it successfully enters my (LDAP) email address, and the email address field has focus, so I can “submit” the form successfully by hitting the Return key on my keyboard, at which point the password field appears, is also auto-filled with my password, and has focus. So far, so good.
However, if I then press the Return key, nothing happens, and the form doesn’t get submitted. I have to either click the form submission button manually or tab to it and hit the Return key to submit the form.
Given that the password field is focused, and my password is filled in, I would expect to be able to hit the Return key to submit the form when the password field has focus.