Thank you sir or madam, I tip my hat to you as you retreat into the shadows. I didn't post for over 600 days after creating an account here, and still like to think of myself as a lurker at heart.
Being able to collapse and expand branches of the conversation tree might be helpful by itself; I get lost sometimes trying to remember who is responding to whom. You suggest a good additional idea that branches started by a user you have muted be collapsed by default, so you can choose to see the passive aggression.
Everybody likes choice, right?