> never replace a terminal based app, with a GUI based app and expect productivity gains

I can imagine this being true. It seems that almost the whole software industry has failed to grasp the distinction between an appliance and a tool. An appliance you expect almost anyone to be able to use without training. A tool, well you are expected to learn how to use it, and after that, you are much more productive than before. And most software seems to be moving towards appliance.