Given the degradation in quality by having packets routed through translation servers to go between IPv4 and IPv6 parts of the internet, I'm not sure I'd consider having IPv6 enabled is a good thing just yet. The infrastructure's not really there. Many of the flaky networking issues on ubuntuforums.org are resolved by commenting out IPv6. Perhaps a commented version as default with instructions to uncomment if you need IPv6 would make more sense?
Given the degradation in quality by having packets routed through translation servers to go between IPv4 and IPv6 parts of the internet, I'm not sure I'd consider having IPv6 enabled is a good thing just yet. The infrastructure's not really there. Many of the flaky networking issues on ubuntuforums.org are resolved by commenting out IPv6. Perhaps a commented version as default with instructions to uncomment if you need IPv6 would make more sense?