Too much legibility can kill a new idea or scene, especially early on in its life.
Legibility creates clearly defined edges and creating clearly defined edges on an idea or concept can stifle its further growth as people can confidently assert “this is what this thing is!”
Legibility makes it easier to make a claim on an idea. With many people laying claim to it, any shifting in the ideas becomes similar to decisions by a committee. Decisions made by committees lead to median results.
On the scene front, legibility just makes it easier for people to get in, which can lead to the phenomena described in Geeks, Mops, and sociopaths in subculture evolution. Remember, Effective scenes are smaller than Dunbar’s number.
Too much legibility disavows the importance of Tacit Knowledge. (Tacit knowledge feels opposed to Aristotelian legibility). In situations where tacit knowledge is actually critical this can mean death.
On the flipside In order to extend a heuretic it must be legible to you. The synthesis might be that Legibility is not an inherent property of a thing — it always involves a subject and an object. That is, legibility isn’t a binary thing: the trick is to make the ‘right’ things legible to the ‘right’ people.