I've been working with clojure professionally for over 4 years. The default navigation in emacs is non-existent as far as I can tell and only works at all once you've loaded the source into the REPL. Even that only works for resolving top-level vars and doesn't work for local bindings. Admittedly I tend to use cursive so this may have changed recently. But that still doesn't help you understand the argument/return types of functions etc.