The account configuration screen should probably not enable the next button until the user has added a user account in addition to root. The fact that you have to press the Add button in graphical mode, but not in text mode, is quite confusing at the best of times.
Or how about just disabling Next if some user accounts details are filled in but not yet added? It's just not clear whether or not you need to press the Add button after having filled in the details.
We cannot force people to create user accounts, as there are machines which have no need for user accounts (servers, machines residing on NIS domains, etc.) The way that screen works, without forcing the creation of user accounts (which we are not going to do) we cannot disable the Next button, so . . . Hopefully it will be a little more intuitive in the next release.