As of now my understanding is that with POW an attack by one or multiple goverments could be orchestrated just by raiding mining farms (which can be easily identified given the electricity bill) and confiscate mining equipment + taking down pool servers and terrorism trough media ....that imho is more than enough to permanently compromise bitcoin (no need for a 51% attack)
How will Casper mitigate those risks? Will the IP of the validators be public? How will the problem of DDos be handled?
Off the bat the only clear advantage I can foresee is that if a validator is censored/taken offline ethers would be automatically redistributed to other validators (hopefully) around the world in various different jurisdictions opposed to the mining equipment being confiscated , that being said Casper would still be vulnerable to a scenario where cohercitive force and terrorism trough media is being used by governments to discourage other holders/stakers to step in and become validators themselves , in such scenario even with the use of dedicated servers to run validators the real life identity of the holder would be compromised , not to mention the loss of ethers and the legal troubles for the the hosting company .... Finally this brings in the most important question : What would happen if nobody is willing to stake?