Huge Clojure fan here, been using it professionally for 9 years.

This is a good article, highlighting a couple of the warts, which I think is a missing element for most people who like a language.

I completely agree with the nil punning observation. One of the issues pointed out in the article that resonated most with me is functions in the standard library usually (but not always) nil pun. You get used to nil, so when the standard library does throw a runtime exception, you're surprised. For example:

(:foo nil) => nil

(int nil) => exception

Overall great article.