This command returns only once all of the jobs that are marked 'stop on unmounted-remote-filesystems' have a chance to stop. Do you know what jobs on your system are affected by this? Normally it will return quite quickly. Unless you're using NFS, it's possible that /etc/init/networking.conf is the slow-down; it does quite a few checks before stopping, but these shouldn't have any effect unless you have network block devices.
This command returns only once all of the jobs that are marked 'stop on unmounted- remote- filesystems' have a chance to stop. Do you know what jobs on your system are affected by this? Normally it will return quite quickly. Unless you're using NFS, it's possible that /etc/init/ networking. conf is the slow-down; it does quite a few checks before stopping, but these shouldn't have any effect unless you have network block devices.