It was ahead of its time in UX, but rather behind in the foundations. It's a single user system with no real security, and there was no system of shared libraries - to share code between applications, it was usual to put the shared code in a kernel module and call the kernel. Even the standard C library worked this way. Amusingly, when you invoked the system console -which was at a lower level than the gui system, ef…
I can take or leave shared libraries. They seem to cause a lot of trouble, but so do statics, so I'm on the fence there. But in the context of when this was released it's a non-issue.
I'll give you the CLI thing though. If the CLI couldn't be full-featured in a window that was an oversight.