So far those proposing proof-of-stake have failed a simple test:
I haven't heard of one proposal that allows pools of peasants to be stake miners. Effectively these would function as cryptocities as there would be an incentive to keep cryptocoins within communities. This would create feedback loops and self-propelled microeconomies.
From the wiki (myths):
In more pragmatic terms, "fairness" is an arbitrary concept that is improbable to be agreed upon by a large population. Establishing "fairness" is no goal of Bitcoin, as this would be impossible.
I'm not talking about fairness. I'm talking about proof-of-stake that includes everyone who pulls an equal amount of weight. There's no difference between premining and early adopters building bunkers. One versus a few still leaves many in a second class category. If you think you can push special tier privileges and expect ppl to go along with it, you're delusional. If you think there's nobody who can repeat the success of bitcoin, you're blind.