Personally I'm not a fan of animals like Pit Bulls. I'm even less of a fan though of government controlling our lives.
I wouldn't support legislation that requires special insurance or that sort of regulation.
If an owner of any animal would like a microchip that would be their choice. I've heard they work in the case of lost animals.
We are all responsible for what we do and what we fail to do. If an animal of any kind gets lose and attacks a person I'd expect that animals owner to be held responsible accordingly (including pain and suffering) and consider the need to have the animal put down.