[creeble]

+10 on this. The first thing I noticed years ago from running a systemd-based distro, is that shutdown (thus reboot) got stuck in "...waiting for xxx to terminate" for multiple minutes. This had never happened before, and there were never consequences from it not happening. So it was (and remains, in many hard-to-debug cases) strictly a drawback for systemd-based systems.

[codedokode]

It could be a bug in a third party service that didn't shut down properly or wasn't integrated with systemd properly. You should not put a blame on systemd without investagating first.