I don't think anyone would accuse Dan Brown of being a very fancy writer, but in my experience, most people who hate his work actually hate it for the stories. Dan Brown's stories seem to have the same problem as rushed newspaper articles — they seem clever and interesting when you know nothing about the topic, but if you have a passing familiarity with any of the facts of the story, it becomes painfully obvious that the author is bullshitting their way through gigantic holes in their knowledge of the world.