So what is the plan to continue to support building cpython itself which depends on Distutils? Currently the build bootstraps itself without the aid of an existing Python interpreter instance. There would also be major impacts across the whole cpython development process. For example, there are many open Distutils issues in the bugs.python.org bug tracker. We need a plan on how those are to be handled (and that should take into account the expected transition from b.p.o to GitHub issues).  People will continue to submit issues agains Distutils there so triage team members and core developers need to know how to handle such issues.  What if an issue applies also or only to a previous release branch (i.e. where Distutils is still in the repo)?  What about Distutils documentation in the Python docset?  THose are just some off the top of my head.

I don't think any of these issues are necessarily blockers but they need to be planned for and reviewed.  I think a PEP is definitely in order for a change of this magnitude.