A non-trained person is unlikely to be reinstalling their laptop OS. If someone trained does do a reinstall for the user they're not going to be happy finding it was on a single partition. You have a point about allocating space. That's why the canny installer does the partitioning under lvm2.
For and server (and, in fact for my laptop) there's also a partition for /srv.
Biting the hand that feeds IT
