[ProxCoques]

Indeed. What if the cli had both natural language syntax, large alias/synonym matching, and command prediction (eg similar to Gmail's recent feature)? That might reduce the non-discoverability issue to about the same as most direct manipulation ui (where you have to look through menus for the "right" item to click on).

[cgio]

Mathematica has something akin to command prediction and it’s also a very nice way to learn the language.