Also, the canonical way to do file I/O in Python 3 is the `io` lib, therefore it would be a bit of a shame to have separate, non-integrated `aio_*` functions.
I disagree. We also have posix.open, posix.dup, etc. We always expose POSIX functions in the posix module (except for the socket functions, unfortunately, and a few other exceptions), and I see no reason to break with this tradition. The io module should be thought of as sitting on top of the posix module (and it initially was).
Also, since the `io` lib is already supposed to support non-blocking IO, perhaps it would be valuable to stress this support and propose any interesting patches for fixing and/or improving it.
I think that's entirely independent.