Great post, thank you for that. One possibility that we are considering to minimize economies of scale effect in the POS process is to introduce a haircut for nodes holding amount of coins far in excess of required minimum. For instance, if it is required for nodes holders to hold 1000 coins and one node, to increase its influence in the confirmation process would hold 100,000 coins, this node vote could be reduced by some formula and instead of voting with 100,000 coins it would vote with 65,000. Just a thought….