Emacs is not complex at all, but it's easy to mess up if you don't do the C-h t tutorial and read the Emacs Lisp Intro. And if writing a couple lines of lisp to set up Cider is to difficult for someone, what will he do with Clojure?

The thing with Emacs is that it's a programming environment in which you're supposed to program. People want it to work like they want out-of-the-box, but that's like asking the Ruby interpreter to write your RoR application for you. With Emacs you don't reach median productivity on day one but maybe after a week or so, but then on your productiviry will increase and increase. But with other tools maybe you reach the median productivity on day one or two, but you stay thereabouts thereafter. And they eat up all your ram.