I don't really see how benign communism would be sustainable. In order for communal decision making to be practical, some form of representative hierarchy needs

I don't really see how benign communism would be sustainable. In order for communal decision making to be practical, some form of representative hierarchy needs to form. That brings the concept of leaders and that brings concentration of power. With power comes privileges and you're then relying on none of those leaders exploiting their position for personal gain so that it doesn't devolve into a classist society of ruling classes Vs serfs. In my eyes communism is fatally flawed. Inequality is inherent in human society at scale. Better to accept that fact and design the society with mechanisms that try to keep it in check.