The base corruption mechanic isn't about simulation but about game balance - no civ has lasted more than a fraction of the timeline Civ represents, so I find the realism argument weak. That doesn't mean I agree that you should be as powerless as you are to deal with corruption in the game, however
More buildings should lessen corruption and, if there isn't already, there should be a max cap of corruption after which these buildings should do their thing. It looks almost like the game hits you with the over max cities corruption, then piles the distance from capital corruption on top of that. End result is that Police Station and Court House wind up having no noticeable effect for distant cities. If corruption was set at a finite value that wasn't constantly recalculated then these buildings would actually do something.
One thing I added to my games was to double the cost of Intelligence Agency but give it the same ability as a Forbidden Palace. You can't build it in distant cities without a leader, but it's still a late game way of ameliorating corruption without changing the corruption mechanic overmuch. I figure my spies can keep a little eye on the home front as well as the foreign powers.
