In general, experimenting more. You've tackled the narrow use case of a single question with answers, but is that all SE can be, or should be? The thing that I think SE is most lacking is better ways to tackle the sheer amount of data on the site. There's a lot of information there but in general it's not very well organized. Go back to the original announcements about the launch of SO and see what it was supposed to be and how it has either lived up or not to those ideas.
Try this thought experiment: if a stack exchange competitor showed up tomorrow, what sorts of features would it have to have to make you start waking up in a cold sweat every day?
Try this thought experiment: if a stack exchange competitor showed up tomorrow, what sorts of features would it have to have to make you start waking up in a cold sweat every day?