John Patricelli wrote an exceptionally good post on MMOs as a virtual government. It's extremely thought-provoking.
I do have a couple of quibbles. For example, sometimes changes are made for reasons other than controlling player behavior. For example, John cites the tremporary window where you can trade BoP items with other people in party as a reaction to ninja looters. It's far more likely that this was done so that people could correct genuine mistakes, where someone accidentally rolled need, or the item was master-looted to the wrong person.
That's a general weakness of attempts to legislate good behavior through programming. It's often hard to distinguish between someone actively griefing, versus a genuine mistake, or someone who doesn't know what the "right" thing to do is. The classic example is a newbie hunter joining a group with his pet on aggressive. Very annoying, but it's hard to tell if it is a griefer or a new player.
(Though, 99% of the annoyance could be removed if Aggressive was disabled in instances. The new Defensive is more than good enough for group play, even for a hunter who doesn't micro-manage their pet. To be honest, I don't really see why Aggressive pets are a good idea to start with. The new Defensive could be Aggressive and bring back the old Defensive. I'm not sure it's good gameplay for the Hunter to ever lose control of her pet the way Aggressive does.)
I would like to point out the very first example of Blizzard attempting to promote good behavior via game rules: the language barrier between Horde and Alliance. It was done in order to remove trash talking from the PvP game, or at least move it to the forums.