Currently we have anaconda for Fedora 18 designed as a hub with spokes. One of the spokes is the software selection task.

are a few reasons why it may be desireable to move it from anaconda to First boot.

a) Simplify anaconda functionality
b) Reduce the livecd size so that it is under 700megs
c) For smaller systems (netbooks, or systems with 1 gig of memory), allow the firstboot to specify a larger set of installable software. (Eliminate the mutually exclusive selection imposed by Fedora 18).
d) One gig systems do not have sufficient memory to install every option within the Gnome choice. Ditto for some of the other DEs.
e) If software installation is moved to firstboot, Fedora is already booted, and firstboot software installation (yum or whatever) can take advantage of the
/home/user folders increased disk space availability.

The above are just my thoughts after having to do the fedora installation twice because of d)

I am not a Fedora internals person and I really do not know if my idea is practical. It may not be if the livecd option is one reason for not considering this idea, there may be others.