She’s such an important person both for Solarpunk / Lunarpunk and speculative fiction in general as well as Anarchism and related movements

In my opinion, without introducing the constraints imposed by the story, asking the question of "will a certain form of anarchism bring bureaucracy or mediocrity?" seems premature.

As far as I remember, the constraints Le Guin imagined were:

• Anarres had gone independent during its settling, and was very resource-poor, the chief activity of its people focused on securing basic necessities

• their tendency of anarchism favoured "governance" by sortitioned committees

• their tendency of dividing labour favoured people changing their place of work and residence, and generally seemed to favour a state of "flow" as opposed to permanence

• their reproductive habits also seemed to favour a succession of different partners as opposed to permanent alliances

• their society had an external threat present: the planet Urras which Anarres orbited was resource-rich and people lived in hierarchies there (some of the hierarchies being capitalist, some communist)

• they were not alone but there existed an interstellar community of sorts, Urras had relations with other civilizations, including one which originated from Earth (and Earth was barely habitable due to human actions)

• their attitude to the host planet was isolationist, widespread communication did not exist, preventing anarchists from discussing the merits of planetary ideologies and earthers from discussing those of lunar anarchists

...for me, the question of "does sortition bring mediocrity?" has popped up several times. On large scale, I advocate sortition as a political system whenever possible (on small scale, informal do-ocracy seems to work up to a certain point where contributions get unbalanced).

The ancient examples (Athens, Florence, etc) do not suggest that sortition will bring mediocrity. However, a sortitioned person does need auxiliary bureaucracy to be effective at their job - one can't expect Joe Random to get sortitioned into a parliament today (note: Le Guin's story had no central parliament but many distributed committees) and make good quality decisions tomorrow.