Wrong target
Taking down the c&c servers is never going to be a long term solution. The zombies themselves need removing from the network.
I'm usually against getting the government involved in matters like this, but people with zombied machines need protecting, and there are shedloads of them. I think they should introduce legislation to force ISPs to detect and sandbox zombied machines on their networks. This would have a real impact on reducing credit card and identity fraud.
If one major country does it, and it's successful, many others are likely to follow.
