All of these are, in fine, the community's job. Moderators have access to tools that can facilitate things, for example we can merge tags and delete questions, but community moderators do not make the rules. So what else should we, the community, do? How can we moderators help?
We need more questions, and more users - i.e. we need to promote the site.
Stop closing so many questions. Hyper-sensitive admins destroy a site faster than anything. I've looked around and seen so many closed questions it makes me want to bugger off.
If it ever gets to the point where there are a zillion questions and so off-topic questions take up significant resources, then ok. Until then, loosen up. You closed someone asking for a sci-fi recommendation because someone determined it's off topic. Blerk.
Loosen up. Really.