Agree on ISPF being a great editor. It was trivial for new users to pick up, but at the same time had a rich feature set.
My favorite part was its support for folds, or what it called "excluded" lines. You could issue an initial command that excluded lines you wanted to ignore, and then issue subsequent commands to operate on lines not excluded, or "NX". Very nice. I occasionally wish I had ISPF while I'm in the middle of a Vim session.
Btw still think ispf is a great editor. Slimv vim with linux/macOS is better as lisp is better.
Cobol and 370 assembler is so 1960s. Both are 60s technology. And in fact car and cdr from ibm mainframe, not this arch?
But slime and ispf make some bearable.