Please include a simple mechanism to add PAM modules to the system-auth stack. There are more complex setups than authconfig allows to configure and I don't want to add them to every PAM service configuration file or rewrite /etc/pam.d/system-auth every time authconfig was called. A simple configuration containing a list of additional lines to include in system-auth would be eough.
I'll consider this for in the development process for FC.
Your proposed solution wouldn't be universal enough. The PAM configuration is now written in system-auth-ac file which is then symlinked from system-auth, the symlink is not overwritten so local PAM configuration is now possible. You just create for example system-auth-local and change the /etc/pam.d/system-auth symlink to point to that file. You can also 'include' the system-auth-ac if you just want to add some pam modules before or after the system-auth-ac configuration.