Regardless, the last person who seems to figure in their mental audience is the naive student, seeking comprehension and insight. A good exposition is not concise . It is lengthy, leisurely, slow like a patient pedagogue. A good exposition is not abstract . A good mathematical exposition is not minimalist .
Minimalism is just a synonymn for pedagogical sloth.
A good exposition over-explains, is redundant, gratuitous, pedantic. The amount of time wasted by the expert who must skim through a few paragraphs of unnecessary explanation is but a thousandth of the amount of time wasted by the novice student, who spends an afternoon perplexed by a single mysterious mathematical statement which he could have understood in five minutes, had it been properly explained to him. A good exposition is not clever . Clumsy proofs, on the other hand, employ awkward, crude tools, which have many applications. This method is slick, but it doesn't generalise.