Speeding up openSUSE 13.2 boot

I bought my wife a "new" old Thinkpad (T400, Core2 duo) to replace her old compaq nc6000 (Pentium M Dothan). Of course I installed it with openSUSE 13.2. Everything works fine. However, we soon found out that it takes ages to boot, something around 50 seconds, which is much more than the old machine (running 13.1 on an IDE SSD vs 13.2 on a cheap SATA SSD in the T400).
Investigating, I found out that in 13.2 the displaymanager.service is now a proper systemd service with all the correct dependencies instead of the old 13.1 xdm init script.
At home, I'm running NIS and autofs for a few NFS shares and an NTP server for the correct time.
The new displaymanager.service waits for timesetting, user account service and remote file systems, which takes lots of time.
So I did:

systemctl disable ypbind.service autofs.service ntpd.service

In order to use them anyway, I created a short NetworkManager dispatcher script which starts / stops the services "manually" if an interface goes up or down.
This brings the startup time (until the lightdm login screen appears) down to less than 11 seconds.
The next thing I found was that the machine would not shut down if an NFS mount was active. This was due to the fact that the interfaces were already shut down before the autofs service was stopped or (later) the NFS mounts were unmounted.
It is totally possible that this is caused by the violation in proper ordering I introduced by the above mentioned hack, but I did not want to go back to slow booting. So I added another hack:

• create a small script /etc/init.d/before-halt.local which just does umount -a -t nfs -l (a lazy unmount)
• create a systemd service file /etc/systemd/system/before-halt-local.service which is basically copied from the halt-local.service, then edited to have Before=shutdown.target instead of After=shutdown.target and to refer to the newly created before-halt.local script. Of course I could have skipped the script, but I might later need to add other stuff, so this is more convenient.
• create the directory /etc/systemd/system/shutdown.target.wants and symlink ../before-halt-local.service into it.

And voila - before all the shutdown stuff starts, the nfs mounts are lazy unmounted and shutdown commences fast.