I've also considered going to work in Iraq, as I have many friends who have made a lot of money there. And I had plans to travel to Syria before the civil war started I think in 2010... still wish I had gone. Not much left anymore. I wouldn't mind going to Libya. And North Korea I would probably pass on though I've heard trips there are pretty interesting. The rest... yeah I'll skip those.
It would be as close as we can get to actually going back in time though and it is a pretty unique country.
Even though I would travel to some of these places I think the list is pretty reasonable with the exception of Iran. Though I know it is dangerous (mostly because the government is likely to incarcerate you for spying), compared to other countries on the list it doesn't really seem to fit. I know so many people who have visited Iran and had a lovely time doing so.
Iran however I don't think fits the list at all. From what I know it's pretty stable and safe, at least if you stay in tourist areas. Probably only on the list because of US relations.
Level 1: Exercise Normal Precautions
Level 2: Exercise Increased Caution
Level 3: Reconsider Travel
and Level 4, the highest, Do Not Travel