To me, this is almost like asking, "Why, since it is 2012, is the Halting Problem, such a problem?" I don't know what 2012 has to do with functional programming languages, though ... seems like there was this language a long, long time ago, in a far away land ...
What made Clojure stick out for me was its easy access to the vast java libs, and its philosophy on concurrency. Both (I could be very wrong) seemed novel in the functional world.
