I think one reason the arch wiki thrives is that it IS a generic linux wiki.
The arch wiki describes the upstream package.
I say this because Arch tries to use the upstream software as-is, and describes requirements and helps make configuration choices.
Other distributions tend to make the choices for you, configuring and modifying upstream to fit the distribution.
With respect to a wiki, this would be another layer of documentation to add. Describe the package, describe the distro, and explain the configuration choices.
The arch wiki could expand to support distro switching, with each distro having its own domain, and all that could link back to a general linux wiki. It'd be beautiful.
The arch wiki describes the upstream package.
I say this because Arch tries to use the upstream software as-is, and describes requirements and helps make configuration choices.
Other distributions tend to make the choices for you, configuring and modifying upstream to fit the distribution.
With respect to a wiki, this would be another layer of documentation to add. Describe the package, describe the distro, and explain the configuration choices.