We have this super small, 30-member Discoursce install, and I wouldn’t imagine using it without the 5-avatar row. Super useful, exactly for the reasons you stated.
Now, I realize that we are discussing defaults (same thing in the clown vomit thread) and I trust that you know better. As long as it’s customizable, either via CSS, a checkbox or by modifying a template, I’m OK with whatever decision you come up with.