I am always impressed how powerful and efficient shell scripts are but the syntax is just a killer. Is there a strong reason why all shells have this crazy syntax? Is it not possible to create a shell with a more expressive syntax like Java, C# or whatever?

scsh (https://github.com/scheme/scsh). Plus, it has the best Acknowledgements section of any technical documentation ever (https://scsh.net/docu/html/man.html).