But anyway, what of Paul Stzorc's response to Vitalik? Riskless counter-contracts. In general with PoS it seems to me that Vitalik and the other PoS people are falling into the "make the security model confusing enough that even really smart people can't understand it = good security" error. Sure, PoS doesn't seem confusing, but with things like stake-grinding plus an endless parade of more unfamiliar-to-security-researchers workarounds it optimizes for a security model that's difficult to poke holes in during debate, but that a motivated attacker could eventually figure out how to attack precisely because it's too opaque to know that what the attack vectors are so that they can be defended against.
I maintained since 2013 that PoS can't pull from a large enough pool of entropy. The randomization of order can be gamed. Note a natural source of external entropy can't be employed (as this would require centralization).
The excessive use of resources in PoW can be easily solved by lowering the debasement rate (and transaction fees), but before you do this you have to remove the 50+% attack. (So what is the point of the mining eh? You'll have to wait for the details to be revealed, then it will make sense)
And now I am really telling you too much of my design so I will STFU now.
Hopefully I have made my case about Bitcoin threats and the need to keep an open mind to new crypto-currency designs. I don't want to repeat all that I wrote in this thread again. Readers can go back and re-read all my post in this thread someday if ever it is worth doing so.