I don't see any reason not to install ensurepip in this situation. That flag controls whether or not ``python -m ensurepip`` will be executed during the install, but ensurepip itself will still be installed. It is not an optional module
Yes I am aware of that. However ensurepip is also required to maintain functionality of the "venv" module in 3.4. See the guidelines in http://www.python.org/dev/peps/pep-0453/#recommendations-for-downstream-distributors which explicitly mentions the fact that this is functionality equivalent to the same bundling that occurs in virtualenv and I've yet to see a distribution not include that and not make an exception to the bundling policy.
As Donald notes, this was explicitly covered in the PEP: the onus is on the distros to make ensurepip and pyvenv work in a way that complies with their debundling requirements (e.g. by using rewheel, or redirecting to the system installer). The "--without-ensurepip" flag is there to disable running it at install time. Fully removing the ensurepip module is not a supported configuration - if a distro wants to do that, they're going to have to carry a patch.