Diversity and independence are important because the best collective decisions are the product of disagreement and contest, not consensus or compromise.
If small groups are included in the decision-making process, then they should be allowed to make decisions. If an organization sets up teams and then uses them for purely advisory purposes, it loses the true advantage that a team has: namely, collective wisdom.
No decision-making system is going to guarantee corporate success. The strategic decisions that corporations have to make are of mind-numbing complexity. But we know that the more power you give a single individual in the face of complexity and uncertainty, the more likely it is that bad decisions will get made.
The Wisdom of Crowds
by James Surowiecki