Staking coins, in general, have an issue with centralization as the one with the most coins generally gets the most rewards. Anyone could just buy up Steem and thus buy up power over the chain. DPoS seeks to make it harder with voting, but clearly, Steems voting system isn't full proof since he was able to make new sock puppet accounts and attempt to game the system.

I think this calls for an age-based DPoS attribute for witnesses. The longer you own the staked coins then the more influence you can have on the chain. It could help, but that may just centralize things further for whales who are witnesses. Some of these changes will end up helping whales and hurting new users in the long run.