imho, hierarchy is natural to mammals like us – but we, socialists/anarchists – must reduce as much hierarchy as possible and make all structure and leadership accountable to the group. This is difficult because cliques and circles of friends and so on form even in the most egalitarian of organisations. Mostly because it is easier for people, it easier to let people who want to do something do it, thus forming a hierarchy.
Most orgs i have been in have what i call a 'dictatorship of the doers' while others cannot do as much or choose not to, or perhaps feel intimidated or personally lack confidence or don't have the skill to 'do'.

Thus, the 2nd issue: distribution of responsibilities, of skills and the need for group trainings (which often do not happen within groups)

– @jd

The problem with 'Consensus' as it is usually practiced (in my experience) is that the knowledgeable, the skilled, and the self-confident will always dominate.

This can be ok, actually – but if your org is not working internally to distribute knowledge, teach skills, and build self-confidence of members to act on their own, then Consensus is just like any other hierarchy-based organisation.