[GianFabien]

I recall there also was em which displayed a single line as it changed. With ed I used to invoke the 'p' command constantly to confirm that my changes were correct. With em it was done for me automatically.

IMO Unix utilities evolved along with the concurrent advances in technology. If anything, the pioneers were far more concerned about functionality than aesthetics. The earliest UX principles only emerged from the work on Smalltalk at Xerox PARC.