Debian sid is roughly equal to most other distributions official releases. One of the main reasons that Debian stable and testing are always behind other distributions is due to the fact Debian requires much more out of the packages, by requiring them to work on all architectures and without major bugs. In some cases they lag even in Debian unstable due to the fact that the upstream doesn't properly test their releases and integrate bug fixes, for example XFree86.
I do think that having an automated check for packages being out of date with upstream would be nice though. Perhaps if policy required the watch file be present for packages then qa.debian.org could add checks for them to the developer and packages pages. That would make it much easier for maintainers to see when packages are out of date and either update their own packages or ping the respective maintainer to see if they are still around. Chris