We're trying to migrate all packages away from /etc/sysconfig/i18n, /etc/sysconfig/keyboard, and using of HOSTNAME= in /etc/sysconfig/network. See tracker bug 881785 for more details.

Looking at the sources, it appears that Anaconda writes to both the old sysconfig files and to the new systemd-supported config files in:
 pyanaconda/keyboard.py
 pyanaconda/localization.py

We're trying to migrate what we can to use the new config files for F18, because the current situation with the two sets of config files is already buggy, inconsistent and confusing.

I can understand if Anaconda is being extra careful and wants to keep writing both sets of files for F18. However, there's a %post scripts in systemd that deletes the old config files, so writing them seems pointless.