I don't think this was a particular change in approach, to be honest. From the start they were clear (listening to the early podcasts, at least) that they wanted the site to stand as a reference, and to have each question be the best possible question asking one clear thing, with the best possible answer underneath.

Everything else on top of that was gamification to convince people to achieve that. Whether that sort of community becomes degenerate at a certain point is certainly interesting to study, but my intuitive reaction whenever I see a StackOverflow result at the top of some google results is to be joyful, so I feel they've mostly achieved their aims.