I've been pretty happy with the experience of using Python as a replacement for my previous solutions of .PHONY-heavy Makefiles and the occasional 1-line wrapper batch file or shell script. It's a bit more verbose, and I do roll my eyes a bit occasionally at stuff like this:

    call([options.cmake_path,'-G','Visual Studio 16','-A','x64','-S','.','-B',build_folder],check=True)

But in exchange, I never have to think about the quoting! - and, just as you say, any logic is made much more straightforward. I've got better error-checking, and there are some creature comforts for interactive use such as a --help page (thanks, argparse!) and some extra checks for destructive actions.

If you just want to move some files around and do basic text substitution, turning to Python or another other "full fledged programming language" is a mistake. There is so much boiler plate involved just to do something simple like rename a file.

For reference, it seems to be this: https://xon.sh

  XONSH is a Python-powered shell

  Xonsh is a modern, full-featured and cross-platform shell. The language is a
  superset of Python 3.6+ with additional shell primitives that you are used to
  from Bash and IPython. It works on all major systems including Linux, OSX, and
  Windows. Xonsh is meant for the daily use of experts and novices.

Haven't heard of it before personally, and it looks like it might be interesting to try out.

I stopped caring about POSIX shell when I ported the last bit of software off HP-UX, Sun OS, and AIX at work. All compute nodes have been running Linux for a good long while now.

What good is trading away the benefits of bash extensions just to run the script on a homogeneous cluster anyways?

The only remotely relevant alternative operating systems all have the ability to install a modern distribution of bash. Leave POSIX shell in the 1980s where it belongs.