In my opinion, the regulators should focus on exchanges applying KYC and make the exchanges function the same a stock exchanges. If I buy a stock in the US through a brokerage house, they have my info and every year they send me a 1099 with my profit/loss for the year that I give my accountant to add to my income tax report.
Once the exchanges are regulated like that it would be very difficult to launder money or avoid paying taxes on profits.