I think it would be nice that I could take the kernel from the LiveCD and
installed it as is (including moduels) over my new installation PC instead of
building a new one. For sure I would like to do that past the first reboot
but I often got problems where I forgot some required kernel option rebooting
into a "Missing console" kernel critical stop or into a "Missing DevFS"
state.
Then I have to reboot from the CD, remount everything as it was, chroot and
recompile ... It would be really great that the installation start by having
you install the LiveCD kernel with the module get this to be the default
kernel for your installation then once rebooted to that new kernel from the
hard disk you could then start installing/playing with a new version of the
kernel.
At least at that point if the new kernel failed, a simple reboot with the
selection through grub/lilo to pick the previous working kernel would be
enough to get you back inside a working state to debug your kernel.
That installation could also be simplified by creating an ebuild such as
livecd-kernel and having the admin type emerge livecd-kernel to do that step
for him.
This would also make it easier for an installation software to get that step
automatically done.