A couple of concerns I have related to this postsite are:
The uncertainty as to its future is actually a pretty severe demotivator. despite understanding that more than likely, the posts from here would be migrated to either Physics or Space (or a mix), and they would probably be quite well received, generally. (I am a member of both now).
We have a limited audience to which to test how strong the posts are in a private beta, the true litmus test would be if/when we go public.
Looking at the front page just as an example - as this is the first thing that would be seen by any visitor - we do have quite a number of interesting and thought provoking questions - many are either not-so-easily google-able, and some of the ones that are, turn out to have answers that are not as straight forward as one might think (e.g. "Which is the nearest exoplanet?").
Also, I am not sure about this, but many seem to be missing the fact that our knowledge in astronomy is changing with new discoveries, so what may seem mundane (and 'google-able') now may be the focus of answers about something new.