[senzilla]

POSIX shells does indeed have many problems, including lack of data types and various security limitations. I like the point OP is making that shells should focus on being interactive, but not so scriptable.

For scripting, it's better to resort to a simpler solution that doesn't even need complexities like parsing or data types. In a Unix environment all you need is the ability to compose commands together. This is what execline is for:

https://skarnet.org/software/execline/

[hnlmorg]

There are a few modern shells that do include data types and fix a number of security issues that more traditional POSIX-like shells (Bash isn't technically POSIX) suffer from.