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.