Today I stumbled over a blog post by Dhanji R. Prasanna, a former project member of Google Wave, who describes how even the most talented people cannot come across the complexity of large teams – and what impact it has on motivation and success.
Ever since we launched the project with the codename Phoenix, all kinds of people bugged me that one of our primary goals should be to become a reasonably big team so the risk is spread on more shoulders. I can understand that some fear the Bus Factor, but adding more developers to the team doesn't solve it really.
We are and always have been open to inviting new members to the team. What's important though is that we can divide the big team into smaller, independent teams of 3-4 people who can pretty much decide on their own.
I recommend reading Dhanji's blog post about the Mythical Man-Month at the Google Wave project.