[TACD]

So why not incorporate blocks as a signal for the ranking algorithm? The simple version is every person that blocks $USER causes a -n modifier on all of $USER's content; more complex versions could scale the modifier with the number of people (or the combined "reputation" of the people) blocking $USER or shadowban them once x% of posters block them.

Open to abuse? Potentially, but so are a lot of community voting features, and reliably muting serial trolls would be a useful feature for a lot of social sites.

[Avicebron]

One problem I immediately see with this is that it's difficult to define what a serial troll (excluding bot accounts) is vs someone a community doesn't like for whatever reason, using a downvoting system at least provides some leeway in discussion that is on the boundary of what is and isn't commonly accepted for a given comment at a given time within a conversation.