Okay I see what you're going at. I suppose some nations will go more local with a lighter rule from above, and others will be able to go hard authoritarian with rule from a powerful central government.
With Italy I'm just concerned that if localism gets too far a grip it leaves them extremely vulnerable to the likes of France and 'Germany'.
Yeah. I wasn't thinking of some cyberpunk-turned-steampunk setting in Italy where 19th century versions of mob bosses are running the towns as their personal fiefs- though that may happen in a few areas because that would be coooool- I just thought that given the nature of the cataclysm, surviving local ties would flourish in this, and the monarchy may take advantage of them. Fascism doesn't go well with organized crime- the state does not take lightly to competitors- but Mussolini's Italy never experienced an extinction event by meteor. In this case the national government could take as much help as possible lest the Germans- or Moorish raiders- prove to be a problem.
As for being vulnerable- well, why shouldn't they be? Not all of the countries will turn out as powerful as the Raj or the Balkans HRE. Italy may turn out to be playing second fiddle, rather like France-outre-Mer or the Sultanate of Egypt. Their agricultural output aside, I don't know what the state of their military was at the time. If it's not up to snuff as their neighbors they may end up being a buffer state.