Re: domain controller is restarted
I agree completely.
The biggest problem is small IT shops where, actually, the DC is misused as not only the DC but also the primary file store, profile store, etc. Even if they have a secondary / tertiary DC, they can't just reboot them because they don't have adequate DFS setups etc. to cope with one server going down.
Hell, I've seen schools who have Exchange on the DC (which is a totally unsupported configuration) because they don't want to have lots of expensive servers running (Most of them haven't caught up with modern VM technology, either).
A lot of it comes from the legacy of 2000/2003 where a lot of functions couldn't be failed-over to other servers properly or easily (e.g. DHCP, DFS, etc.).
Also, because it's a "DC" it's seen as some mystical magical configuration that must never be rebooted even if you have a secondary.
Hopefully as we move forward into VM'd configurations, such a mindset will be phased out.