There are many in the left, particularly the anarchist and anti-authoritarian tendencies, who believe that because all hierarchy and power are bad, there should be little or no structure to our organizations.
However, no matter how well-organized we are, hidden power structures often remain, and these can result in dynamics where some members are doing most of the talking and decision-making, while others are effectively silenced.
A great read on this topic is: "The Tyranny of Structurelessness," by Jo Freeman, published in 1970, but still relevant today.