My intuition leads me to disagree with the suggestion that a small team might be better.

People argue that small is better for security reasons. But one could as well argue that large is better for security reasons because there exist more supervision and competition. Do you rather trust 5 people (likely friends) or a hundred strangers working for fame and money? After all we're talking about a project that will result in the implementation of a superhuman AI to destine the future of the universe. A handful of people might do anything, regardless of what they are signaling. But a hundred people are much harder to control. So the security argument runs both ways. The question is what will maximize the chance of success. Here I agree that it will take many more people than are currently working on the various problems.