A somewhat similar thing I ran into is that existing Clojure code can be incredibly difficult to grok if you don't already know the language very well.

Some of this comes from lisp's minimalist syntax, which makes it hard to even know what kind of thing you're looking at when you're encountering a new thing for the first time. But the problem is also compounded by some of Clojure's more distinctive (and powerful) features such as ad-hoc polymorphism and using maps to pass function arguments.

The closest analogy from imperative languages that I can think of is another language that's famous for being incredibly productive in the hands of a skilled user, but whose code tends to feel kind of write-only: Perl.