Agreed. It's not that it's difficult, it's just that it is so sparsely documented compared to other aspects of the system (where it really shines, FreeBSD is much better documented than a Linux distro of similar size).
FreeBSD really needs a default way to keep the system update, to install packages, and to upgrade release, and to document this clearly in the guide.
It's probably not even very much work compared to the monstrous work that goes into each release. AFAIK these mechanisms are in place and work well (but I've had more experience with OpenBSD myself where these things are always that smooth).