Name aside, the different government systems do work differently. Democracies have more peaceful dissent (protest instead of riot), but harsher police work is more difficult, while kings help with morale and control simply by being present in a region, for example. The rules from who can appoint himself to what also varies greatly according to the government system, and as such you can never have a ruler in a democracy, no matter how tyrannic he is, appoint himself as a duke.
That being said, I do think that the government details are way too *easy* to switch, and have always said so. That might just be me being too old school, though. I otherwise like customization.
There should be penalties, like capital-move penalties, for moving away from the base settings for a given realm type, with the greater the change, the more problems the change causes. A monarchy where the judge is elected by region lords quarterly should have only minor trouble, where a tyranny with a monthly ruler election should be almost impossible to maintain.
Or, make it a one-time penalty, and not a continuing one.
