Earlier quoted context omitted.
I wrote the core of our system in Clojure a couple of years ago, which is pretty high in productivity and actually quite pleasant to work with. Unfortunately as the scale goes up (hundreds of web application routes, sharing code among multiple projects etc) it doesn't feel nearly as nice anymore, and having static typing turns out to be pretty handy. Haskell to me felt exactly like what you described: I could get stu…
Oh ok, I can be wrong about Haskell. BTW, I really like Ceylon, it's very statically safe (more than Haskell I'd say) and very pragmatic (unlike Haskell IMHO, it doesn't seem to focus on maximizing productivity).
Disclaimer: I do not have enough PL type theory under my belt to confidently make this argument.