The one expert, because the others would not be able to reach a decision on which move to play.
I think a key missing component to crowd success on real expert knowledge (as opposed to trivia) is captured by the concept of prediction markets. (https://en.wikipedia.org/wiki/Prediction_market) The experts who are correct will make more money than the incorrect ones and eventually drive them out of the market for some particular area.
With humans on the other hand, there will always be some discussion. And some human experts may be better at persuading other human experts or the combining entity.
I think it would be an interesting thing to try after they beat the number 1 player. Gather the top 10 (human) Go players and let them play as a team against AlphaGo.