I suggest to implement this idea on PyPI first and only later propose it for inclusion in the stdlib (as a new module, or into an existing module). Bikeshedding on names, debate on the appropriate trade-off between correctness and speed, how many functions?, which functions?, etc. can be discussed outside Python bug tracker first. So far, the proposition is quite vague: "Math module method to find prime factors for non-negative int n". Comments on this issue gives an idea of the questions which should be answered first. See also bpo-37132 which proposes another bunch of functions.

Because such module is easy to write and prototype, bikeshedding on details are more likely :-)

An actual implementation may help to drive the discussion, and a dedicated project may help to organize discussions (ex: dedicated bug tracker to discuss each function independently).