If you have an account with a disabled password (like the live CDs do, passwd -d is run), you now get prompted for the password when logging in both via gdm and login. This is a change from the F7 behavior and pretty undesireable from the point of view of making the logins obvious with the live images.
It's actually caused by a change in selinux policy. You can verify that in permissive mode you won't be prompted. But it will have to be solved in pam_unix somehow.