Whether or not the old editors are powerful, they take a very long time to learn, and are possibly unmasterable for most people. Browsability and intuitiveness in an interface is something that both vi and emacs, even in their most modern incarnations, don't really have much of. (emacs is slightly better in this sense because it defaults to be non-modal; easier to understand than vi's smorgasboard of one-letter functionality) They were very good for their era, but today training time is a very important factor and they are deficent in that area.
I use the Python IDE, Idle, as a general-purpose text editor sometimes. That or nano.