We are doing quite well in most of the statistics seen in Area51 but there is room for improvements.
The rate of question/day always was low except few weeks when questions from single users pushed up this value.
This also tells us that it is not so much the number what counts but the overall contributing users, which at times are very few (if any).
The answers/question rate is okay but sadly its declining.
It will therefore certainly do no harm to encourage people to give more than one answer to a question as this makes the essence of all SE sites: choose a "best" answer by counting votes.
More than these statistics I am concerned about the low community contributions to site issues.
Fortunately we now do have a solid base of high rep users to be able to perform "Community Moderation" (i.e. closing and reopening posts, approving edits, improving posts). Thats great, and it is a good step in the right direction.
But the contributions to Meta (where we shape our site) is far too low to proof that we have a lively and caring base of users. We still need to define our scope as can be seen from recent Meta posts but alas there is so little contribution to these posts, so little discussion, not even votes, to indicate that people really care.
Contributions to quality measures such as the site-self-evaluations we already had was low too.
In addition to Meta we should also heavily use our chat as a fine place to discuss issues with the site, topicness of questions, wishes for changes, and more. These discussions there could eventually lead to valuable Meta posts, but this only rarely happens.
So in summary apart from statistics displayed in Area51 I believe we still need a lot of work done on the extent of community contributions to this site matters.