Keep in mind he was also drafted out of High School and has some hicups in his personal life. So while the latter delayed his development some, the former means he has more time to develop.
So really he is doing about what he should for where he is. After his blistering start to pro ball, he had more expectations on him, but in reality he is about where he should be in development.
He still might turn into something special, but I think there is less pressure on him to be that now.