Some time ago I came across a very interesting article by Robert C. Martin (1996 column in pdf) about how packages are supposed to be made up and how it helps building a release, debug and shared-workload strategy. I don’t think it all applies to modern package management, especially for web applications, but it is an interesting perspective that deserves some attention.
granularity.pdf (original source offline: www.objectmentor.com/publications/granularity.pdf)
My summary of his article (as I understood all of it):