"The director of German's central bank believes that bitcoin should be regulated through an international set of rules rather than on a national scale."
Does bitcoin need to be regulated in a global scale?
No, as that will remove one of the most important parts and principles of Bitcoin which is decentralization. Once you introduce a set of rules to Bitcoin, you have to have some kind of organization or group of people regulating those rules. When you have that, it's essentially a government that controls bitcoin's moves. Bitcoin was made so that people could use it anonymously and without having to worry about inflation/deflation from a centralized agency. In fact, if that agency ends up being scammers or people who are not true to Bitcoin, you'd end up with a true mess in your hands.