So far, I like the general trend of this post, and @demotruk’s post above. I think findings ways to simplify some version of your proposed system could be a workable solution, bearing in mind that no solution is perfect. Do you think a system where the tags function as the delivery vehicle for a curator’s entire interaction with a post (so upvoting/downvoting a post can only be done through one of the tags) could solve the problem you outlined in the second half of your post? It feels to me like it would make voting power/steem power inextricable from tags.
On the other hand, it presents a problem for posts that are difficult to categorize.