Bitcoin is not a "payment system" like paypal. Bitcoin cannot be "blocked" by the governments. Bitcoin is designed to be sovereign money independent from the governments. OF COURSE bitcoin is used by criminals, by boy do i have a news for you: criminals use money and bitcoin is money.
As for what the right regulation would be is this: ZERO regulations, absolutely none regulations at all. But since the regulations won't work anyway, the governments can come up with any silliness they want.