Your [Draper's] criticism of learner-centered education seems to come from a very narrow view of what is meant by this and other related modes of teaching and learning. Learner-centered instruction relies heavily on the presence and influence of a teacher and in all instances, the teacher is extremely important. Whether the level of importance is equal is something people on this Forum could take years to decide. The teacher's role is extremely important in constructivist learning environments in planning, designing and implementing the required learning opportunities. The role of the teacher is different, but not less important.
While I think the conversational model of learning has many strengths I don't think you can justifiably argue that it is the only way to go. It seems to me that in the hands of the wrong person, a learning environment based on the conversational model could go as badly wrong and attract as much criticism as any other poorly implemented model of teaching and learning. And then we would all be arguing again on what the next best model would be.