Blocking worked well, on Disqus. 
I decided to block only one person. It was someone who was very obviously trying to dominate every discussion. To impose his authoritarian views. And he was succeeding. By blocking him, every thread suddenly became lighter, cleaner (in every sense), easier to read and use. More Christian.
He is still with us, though now he is mostly using another name.
Do not worry about the quality of the discussion once someone has been been blocked-out. If we think it's better (and it will be), then that'll do for us.
Bring it on.