From the multipart article Where M Knight Shyamalan Went Wrong. In the following quote that summed up the part on Unbreakable it sums up what I feel is wrong with his films post The Sixth Sense, They also discuss The Village, The Happening, The Last Airbender
As solid a film as Unbreakable is, it also wound up poisoning Shyamalan’s career. Ending both of his first two directorial efforts with a big reveal resulted in audiences seeing him as “that guy who finishes his movies with a twist” – a nickname that would grow more and more sour with titles like Signs, The Village, and The Happening. Why didn’t Shyamalan just end the film with David revealing his real identity to his son? What would have happened to Shyamalan’s career if he had? Everything could have been different.