Is Stack Overflow expanding too fast? SOStack Overflow introduces Documentation and Teams in a short time frame. We don't even know how Documentation will be received nor whether the concept holds.
From millions of visitors, how many users are really active? Can they be active on SOStack Overflow, Meta Stack Overflow, Documentation and Teams at the same time? Especially in the beginning I expect Documentation to require much work. On the other hand side, the new concepts might motivate new users to become more active.
Personally, I would have delayed Teams until Documentation had reached a "stable" state with decent content and decreasing demand on new topics.
