Oz, I don't particularly like the idea of deprecating cmd but, realistically, Python development is almost entirely an unpaid, volunteer activity and we do not have enough resources to do everything we'd like to do.  So sometimes we need to make a tradeoff and this seems like it might be a good opportunity to make one that will benefit most people.  It's not my decision to make in isolation so I've sent a mail to the python-dev list asking other core developers and interested parties to comment on Issue33233.  So, let's keep this open until we resolve that issue and feel free to comment there.  Thanks again for your interest!

https://mail.python.org/pipermail/python-dev/2018-April/152653.html