It would be nice if instead of telling people how to hack their system to support $foo, they just made packages for $foo. Then the article would be "apt-get install clojure clojure-mode cl-swank slime".
Packages for clojure and slime exist. We really just need the package to bridge them. Also, ELPA support is decent now (mentioned already).
Yup, but not for clojure-mode. That is the "necessary innovation".
This article is out of date. [1] is the more common fork and it describes ELPA and Leiningen which are now the easiest way to install clojure into emacs.