I wrote about a number of solutions here: Ideas for Future Rule Changes...

Section 13 covers both self-voting and voting-circles and therefore cannot be circumvented by opening another account. Indeed, my thinking since is that it could be an even steeper drop.

As you said, and I highlighted, behaviour that is considered "bad" cannot be eradicated, it can only be reduced to the point where it does less harm. To achieve that requires encoding algorithms that change the balance towards "good" behaviour.

Defining the distinction between the two requires a clear unambiguous definition of what the ultimate aim of the whole platform is; and that should be the focus of the discussion before arguing the pros and cons of various algorithms. Without that, people will be arguing about different strategies without making it clear that they actually have different aims.