One thing I'd recommend adding in the introduction is that even though Emacs can be daunting to learn in the beginning, the effort is worth it because it will eventually become your editor for everything, not just Clojure.
Have to start programming in a different language? Emacs is there for you. Want to write an e-mail message? Emacs is there for you. Want to keep a TODO list or a calendar? Emacs is there for you.
This fact was lost on me when I first started with Emacs many years ago. I had come from using "easier to use" editors like EditPlus and Visual Studio. After trying to use Emacs for a week, I gave up in frustration and didn't touch it for another year. I've been using Emacs for about 11 years since then and I think I wouldn't have dropped it if I had been told "I know it seems hard now, but it's extremely powerful and it can become your one program for everything, on any platform you will ever use".