/usr/src/sys/kern/sched_ule.c:60:2: #error "The SCHED_ULE scheduler is broken. Please use SCHED_4BSD"
All of the upgrade docs I read neglected to mention that vinum no longer works and in fact its vestiges would cause my system to panic upon boot. I've dealt with enough of these sorts of systems that I didn't immediately freak out, and plugging the error message into Google produced someone else with the same problem and instructions on how to switch to gvinum, which happily worked. But that's still sucky.
And after all that I still had the same problem:
"Makefile", line 16: Could not find /usr/ports/japanese/postgresql-tcltk/../
make: fatal errors encountered -- cannot continue
===> japanese/postgresql-tcltk failed
I think in general I don't have the time to track down these sorts of problems. I know enough about how to make Debian run so I'll probably just end up using it for my next server despite wanting to know about FreeBSD. :\