I'm imagining something more like Rexx with quite high level commands. But that certainly blurs the line between programming language and shell.

The reason for choosing higher level constructs is token use. We certainly reduce the number of tokens by using a shell like command language, But of course that also reduces expressiveness.

I've been meaning to get round to Plan 9 style where the LLM reads and writes from files rather than running commands. I'm not sure whether that's going to be more useful than just running commands. is for an end user because they only have to think about one paradigm - reading/writing files.