> Not as part of the release process, but simply regular development of the packages affected by new dependency requirements.  These are logical package hierarchies (i.e., just the names and repositories, no notion of physical "versions" anywhere), so its only when a developer enhances a package to suddenly need an all-new dependent that they would update its package-definition in Installer.

Yes, sure; but I'd argue that we should try to make sure they all actually work as part of the release process. Things get broken...