In what ways is the paradigm too simplistic? Frankly, the fact that there is simplicity in his theories of intelligence makes more of case for him than against him. Most modern neuroscientists trying to understand intelligence have taken such an extreme reductionist point of view that they seem to be increasingly befuddled.
By the way the Ted Talk is from 2003 which is around the time that his theory of intelligence more or less reflected what he proposed in his book, On Intelligence, about Hierarchical Temporal Memory.
Since 2007 I think they've made significant progress. Have you read Numenta's white paper on the Cortical Learning Algorithm. He's also given a much more recent Google Talk on Sparse Distributed Representations.