Blockchain rules could be changed such that the users with 10x the stake could have less than 10x the voting influence. This would mitigate things as long as you have unique identities for each person. As mjhomb points out, making sure everyone is using a unique identity is hard. So such rules would result in people getting multiple accounts in order to have voting power linear to that of their stake, again.
It's always been a problem with Hive rewards.
RE: What Do We Do About Rich Downvote Trolls On Hive?