Sorry, I was sloppy. I meant using it as the system shell. So, processing arguments, I guess, would be less of a big deal.

Convenience features, like ls and other classic shell commands being run without parentheses would have to be handled… I’m not breaking any new ground here, actually this has gotten me to look into xonsh and it looks pretty decent.

Easier, lightweight syntax for shell-like pipes, command execution and catching stdin/stdout/stderr.

Something like Perl's IPC::Run.

Also, more shell-relevant stuff in the default distribution, so that one doesn't need to care about any modules (which is the primary reason for using bash or even sh, those are installed practically everywhere along with at least coreutils and stuff).

But the sister comment clarified it in another way, so this maybe irrelevant.