An excellent post from the blog Farnam Street, which I like, on the arguments against writing.
The basic idea is that writing and reading are not a good substitute for dialogue, and that is hard to disagree with. (Though even a monologue is better than nothing.)
The classic example of the literate non-writer is Socrates, whom we know through Plato rather than from his own writings.
The 20th Century philosopher Sidney Morgenbesser is a modern example, and his recorded quotations here are wonderful. One of my favorites of his, spoken on his death bed: "Why is God making me suffer so much? Just because I don't believe in him?"