Here is the main problem with Proof of stake
https://bitcointalk.org/index.php?topic=615843.msg6751334#msg6751334PoS need some form of trust like checkpointing or web of trust solutions to solve the problem which undermines the trustless nature of cryptocuncies. IMO opinion we should aim for algorithms that make crryptocuncies more trustless i.e. removing dependence of pools etc
Thank you for this, its a very interesting point. Am I correct in thinking that PPC is SHA-256 hybrid in an attempt to rectify this ability to rewrite coin history if you were a large coin holder in the past?