Sam, I believe you are describing the acs-core development process as it exists now, when you write:
"Putting the packages currently called packages/acs-* into packages/core means that they can be tested as a group and released as a group. If features are necessary for the market acceptance of the system, then features can be migrated to core as they mature. New packages, as they mature and gain acceptance, can be migrated to the feature area."
The core packages are listed here: https://openacs.org/doc/openacs-5-1/openacs-cvs-concepts.html
Since that is a useful point of reference, I added it to this wiki page: https://openacs.org/wiki/Core%20Elements%20of%20OpenACS
