Collaborative debate arrives at strong results by not "pre-multiplying" arguments.
Instead, you allow a number of different strong arguments to interact and spar and improve one another, and then synthesize the strongest result.
You arrive at an earned, strong consensus, by convincing one another.
The alternative is to arrive at consensus at the beginning–but that gives you unearned, weak consensus.
With a premultiplied argument you can't distinguish mush from a principled distillation of multiple perspectives.
LLMs give you premultiplied arguments unless you have them spin up sub-agents and synthesize.