Though it is nice to see someones expressions when talking to them I don't think it is needed for this kind of debate.
However, it would be interesting if we had a "chat" section. I'm afraid that the difficulty of moderating would be even greater. The "temperature" of the debate may go up in undesirable ways.
However, it would be harder for individuals to wander without answering a question. It would also be much harder to have time to find support for a position though.
On the whole I'd say this more measured approach is best.