Quicklisp works differently: it gives you a consistent set of libraries. If you want to get the library with some exact version (which may be inconsistent with the current quicklisp dist), you can download it separately and use at your own risk. (And quicklisp will quickload it as well, because it gives preference to local libraries - nice :)

This isn't ideal, but here you have to make some trade-off, because in both Java and Lisp you can't have two versions of the same library loaded at once (actually, in Lisp you can do that with some rename-package trickery, but that's beyond the scope of quicklisp. I wonder, can you do the same thing in clojure? ;)

Considering specifying dev-dependencies. Once again it's not in the scope of quicklisp, which is a library distribution tool and not a dependency management tool. But ASDF, the build tool and dependency management system, allows to do that quite easy: for example, you can define a separate system for dev, which you may load or not load, depending on your needs.

Actually, leiningen tries to do all at once: dependency management, library distribution and building. And that's why it's quite complicated (in the sense of Rich Hickey's complecting, I mean)...