Authentic class discussions are an important part of real learning. The teacher's role should at most play as an artful guide. If a stranger were to walk in the room, they might even have a hard time finding the teacher. Because teaching can often be more about listening, it is important that the teacher's voice not dominate the discussions.
Rather than hearing the teacher asking "who can tell me..." in a kind of fishing expedition for 'right' answers and seeing students sitting in rows with their finger tips stretching for the ceiling as they yelp "ooh, ooh, ooh", you would see students looking and responding to each other while the teacher plays no more than an equal member of the conversation.
Critics of this idea might suggest kids shouldn't be given a blank cheque and that they need the teacher's help to learn.
And I agree.
When traditional schooling is challenged, too often defenders of traditional practices bully a kind of false dichotomy. Either you are for the controlling and dominating teacher who dictates the learning or you are for a teacher who sits at his desk in fear of 'interferring' with the children's learning as they run amok. When phrased like this, even I prefer the former to the latter.
The good news is that dictatorships or anarchy are not our only choices.
For more on my take on this topic, see this article: If only students would STOP raising their hands.