Fair enough; I haven't used Haskell but I know intuitively that a Clojure library won't be able to replicate the sophistication of its type system. On the other hand, the dynamic nature of Clojure is what makes REPL-driven game development possible.

I'm willing to give up some type system sophistication in exchange for that, along with access to the JVM, macros, and so on. Carmack may not agree with that trade-off, but like I said, I mentioned him specifically for his endorsement of functional game programming.