I don't think account-based voting would work particularly well for Steem. A big advantage of holding a large stake in Steemit is the ability to utilize that stake to give content that adds most value to the platform a push. Those with a larger stake should have a greater say than those with the most accounts. There is also the question of curation rewards. How will that work under account-based voting. I believe those with a larger stake also stand to lose out. I believe @steemhunt are considering account-based voting using their SMT, this could serve as an interesting trial run and highlight some of the problems and possibly advantages. They also offer an interesting solution to the multiple account issue I mention.

Here is a link to what they are proposing.

https://steemit.com/steemhunt/@steemhunt/steemhunt-s-account-based-voting-ver-2-diversity-score