The AS400/OS400-like interfaces always seem like they should be more popular super-user interfaces. They seem best at navigating tree-like data but most OS level interfaces feel tree-like these days. I think the affordances work a little better than vim-keys sometimes. A vim-mode option or command palette would be straightforward.

But it would require people to use full size extended keyboard (function F rows, numpads, etc). Which shrinks the user base quite a bit.