So the wickedd-nanny error was indeed related to NFS. Basically SLES 11 would read the fstab sequentially allowing locally mounted filesystem to be placed under NFS mounts (once mounted). Something (I know not what, yet) in systemd presumably reads the fstab differently, disallowing not only the mounts, but also the whole of networking.
Fortunately, I found a little file in /etc/init.d named after.local where I put the local filesystem mounts (the fstab being filled with the NFS mounts). SLES 12 now boots, the configuration files looking thusly:
/dev/sda1 / ext4 /dev/sda2 swap swap server:/export/a /mnt/a nfs server:/export/b /mnt/b nfs # THESE FILES MOUNTED AFTER BOOT # SEE /etc/init.d/after.local #/dev/sdb1 /mnt/a/1 ext4 #/dev/sdb2 /mnt/b/1 ext4
And here's the relevant part of /etc/init.d/after.local
mount -f ext4 /dev/sdb1 /mnt/a/1
mount -f ext4 /dev/sdb2 /mnt/b/1