I feel that you miss the point of WSL. Bash and coreutils have worked on Windows for years. In fact, they ship with git so most developers have had them for years.
The point is compatibility much more than CLI UX. The ability to run that nodejs or Python project even though one of the 1352 subsubsubdependencies has a bug on Windows.
So it's supposed to be more stable than Cygwin? Is it that right now?
I thought Cygwin was very stable and included most things you could want, while also supporting Win7/8, which are the last versions I'm willing to run on my hardware.
There are Linux distributions which contain almost no GNU software, e.g. Alpine Linux which is built around musl libc and busybox: https://alpinelinux.org/about/
EDIT: Yes, there are non-GNU Linux distributions, but WSL is based off Ubuntu specifically and ships with a GNU userland by default.