"""
Regarding the suggestion of separating PEP3121 and PEP384. It might be true that datetime and other modules do not benefit directly from PEP 384, however it is still a fact that the stdlib modules should be seen as a set of reference modules, that are all implemented in a way that complies with the implementation fo the xxmodules.
I have talked with Martin von Löwis about this, and as far as I understood him correctly he also sees the PEP384 refactoring applied to the whole stdlib as a necessary "signal" to other developers to refactor their modules accordingly.
""" (Robin Schreiber, #15390, msg177274)

MvL have recently confirmed this on python-dev: "Choice of supporting PEP 384 was deliberate. It will change all types into heap types, which is useful for multiple-interpreter support and GC."

Accordingly, I've changed the title of this issue and added a few PEP 384 only dependencies.