One big difference is that developing a language for the JVM is not an easy task. Sure, it is easier than developing a language from scratch, but it took, if i

One big difference is that developing a language for the JVM is not an easy task. Sure, it is easier than developing a language from scratch, but it took, if i remember right, 3 years for Clojure to reach its actual quality. Writing a language on top of perl 6 will probably be only slightly more difficult than doing the same thing on top of a lisp, and only because you have to write a grammar since it doesn't rely on s-expressions.