I don't really see why people think that Bitcoin would really change the balance of power.

What hinders people with lots of money to simply buy lots of Bitcoins? Of course not from one day to another, but in small packets over time, so that they own enough to have as much control in a "Bitcoin world" as they have now. I suppose this is already happening to a certain degree.

Or what hinders a government to impose similar legal regulations over Bitcoin comparable to the regulations which exists today? Even if Bitcoin in itself may stay independent, its always possible to regulate the interface between the currency and the "real world". Even if they can't get a grip on BC itself, they can control services like Mt. Gox and all the companies who trade in BC. While it's convenient to be able to trace money flows, it's not necessary to stay in control. You only need to be able to look into the books of one side of a trade to know gains/losses of the other.