[jff]

Do you consider the shell an overly-featured program because you use it to copy/delete/create/link files, install packages, etc? No, because it's a tool which loads up other tools for your use, providing some conveniences like job control in the process.

Emacs provides a lisp implementation. People have used this lisp implementation to write ftp clients, web browsers, and yes even text editing functionality; you then use emacs to load some of that lisp code and execute it. I don't say the Bourne shell fails at "doing one thing well" since people write shell scripts and run them from within the shell.