The problem with eXch is that it's a centralized service in an environment hostile to privacy, or at least to no-KYC exchange. If I were them, I'd simply comply with court orders (ignoring government requests), or at least restrict/review some transactions (flows above $50,000), or temporarily restrict the service when such events occur. While the above solutions aren't ideal, they're much better than losing eXch; we've lost a good service.
When we have something decentralized then we can do whatever we want I am not recommending doing anything illegal here..
The idea of suspending the service for some time seems interesting and minimally effective in the immediate term.
The question is, how long will it be suspended?
The crooks could wait until the service came online to use it. It is true that they certainly would not want to wait, and that could be a positive thing. But hard to know.
Really, setting up such a service without KYC and at the same time being able to avoid being abused by thieves is not easy. The ideal idea still seems that no one had.