That's the motivation behind my Oil project:
Why Create a New Unix Shell? http://www.oilshell.org/blog/2018/01/28.html
I took a very long route to doing it though, first implementing OSH (which will run existing shell scripts, which is close to done, but slow) and then Oil (a new language, not implemented).
This is because POSIX shell/bash has a really strong network effect. zsh and fish are better in many respects, but people are locked into bash because that's what "everybody else uses".
It's analogous to how C has a really strong network effect because e.g. every kernel is written in C. So C++ became a popular language in a large part because it's compatible with C. (Though the analogy breaks down because the Oil language isn't a superset of bash, so we can break free of legacy. The project is though.)
In my mind, I think of Oil as a mix between Python and shell, with some elements of Ruby and JS (blocks, function literals, etc.)