[shusson]

I think searching and linking to existing questions (internally and externally) would be useful.

[JasonFruit]

The useful parts you name sound a lot like a wiki.

[always_good]

SO is a wiki. Except that instead of writing aimless documentation, you can document exactly what people are asking about.

Which makes it better than just about every wiki I've used at a company or Github repo which just get out of date because they are so arbitrary and unfocused.