Clojure is sophisticated [0] but it is hard boiled down to necessary complexity. This means that ordinary language features like interop [1] are well sugared and more abstract concepts like transducers are simple to implement and map well to their description [2]. Stuart Halloway's Programming Clojure captures this idea.

[0] and big for practical purposes like Common Lisp.

[1] you can get at all of Java perhaps better than you can from Java using the REPL.

[2] like lexical scope and continuations in Scheme.