Older novels seek to develop depth and substance in the characters in the books.  Consider the works of Charles Dickens. His characters are full of life and substance.  As you read, you are drawn into the issues of the novel and experience them for yourself.  You have to think and contemplate. Reading an older novel is an educational experience.Not so with Brown's "The Da Vinci Code."  Like much of the newer genre of novel writing, Brown builds interest in his work through mystery and action.  That can be entertaining and fun, but the educational value is limited.  You may "experience" the drama with the characters in a newer novel, the action, excitement and violence, but you aren't stirred deeply inside beyond the thrill of the moment.I enjoyed reading The Da Vinci Code, but was disappointed with historical inaccuracies, theological inaccuracies, and the constant barrage against the Catholic Church (and I'm not Catholic).  A great irony concerning the secret societies in the church is that in "real life," most of the secret societies that work ill will against church and society work outside of any church.Another great irony is the concern for the "bloodline" of Jesus.  The Pharisees in Jesus day laid great stress upon bloodlines.  "We know who we are descended from - Abraham."  Jesus changed the stress from bloodline to that of the Spirit.  Could we search as diligently for the "Spirit" of Christ, that Spirit which led him to give his life as a ransom for many?One character, Teabing, sees our current cultural shift as being away from the thought control and dominance of religions telling us how to live.  Now, we are moving into a new age, "the Age of Aquarius - the water bearer - whose ideals claim that man will learn the truth and be able to think for himself." (P.289-90).  Many today are abandoning our 2,000 year religious heritage rooted in Christ, including his ethic of personal integrity and service.  Is society any better for that abandonment?  We'll see! 

Question: Are those characters simple?
Answer: His characters are full of life and substance