I think this is the right direction in terms of governance. If done right, it will allow voting power to even out among the users and lead to better governance. I would think "account weight" will be a good first step then consider quadratic votes.
As @cardboard pointed out, this is somewhat anti-whale. However, if these rules are only applied to governance votes but not content votes, then the incentives for acquiring more HIVE will still be strong. I supposed there are a number of silent whales who are just trying to earn curation rewards without really wanting to be involved in governance.
In addition, I may be wrong on my understanding of witness voting, but AFAIK, we are allowed to vote up to 30 witnesses and each vote is a full one (i.e. with the entire stake). This was also an added factor on why it was so easy to vote in sockpuppet accounts as top witnesses in Steem. I thought a better approach will be to have your stake split among those that you have voted on (i.e. 50% of my stake to each witness if I voted for 2).
It was really interesting for me finding that paper ... linked above, that basically discuss all the things we are witnessing here now .... also obviously quadratic (root) voting is a know and discussed concept, so we will not reinventing the wheel
The account weight/reputation is something important that should really be further analyzed how to do it properly... it basically replaces KYC on chain.
The last thing you mentioned is a system called one token one vote 1t 1v, that is already in place in some other DPoS chains .... where you can scale your vote to as many witnesses (BP) you want. It was one of the first thing that come up on my radar. Still it does reduces the risk from a Sybil attack but not sure for how much. I guess it is better than what we have now ... 1t 30 v.