The Host/City Founder has whats called Executive Orders, which is a nice way of still having power over the city even when someone else is in charge.
Executive Order 1: Rename the city.
Executive Order 2: Forced change of government.
Executive Order 3: Forced change of group in charge (Only non democratic cities).
Executive Order 4: Disband a group. (WARNING: Deleting the Police is not a good idea.)
Stupid, stupid, stupid.
There should be no host control what so ever. Simply, there is a leader (mayor?) of the player base and if he gains enough control he can create havoc in his own ways, or be a good person and help the city. I've thought about the idea of government change, but then it's no longer a city, it's a nation, city's are within nations, changing your government would be a big problem.
If Springfield, Illinois suddenly chose to be communist or something, we'd be pretty forgeted. The main people doing it would probably be killed or imprisoned forever for treason. If you're planning on adding a system like this, I really suggest re-planning the idea to something like The Nation Project, which would actually be far cooler than a city, with it's own functioning politics and such, of course it'd still have it's old basic stuff like criminals and cops, but you would be able to build off so much more with a nation in your hands. But it'd be harder to maintain as you'd need a handful of people to actually start it; including mayors, presidents, etc. Although, what you could do is simplify it a bunch to a couple basic things. It'd be interesting to see people going for mayor or governor with their advertising.
This would take alot of time and effort to set up, but it would be a cooler, more interesting, and new idea. It'd really be a hit if you did it right.
Don't forget economy too!