The next version of GHC should improve those numbers significantly, but I would also note that there are much more significant reasons to consider using Haskell than the difference between 37k and 43k req/s.

Yesod was only slightly slower than Clojure with Compojure. Also, an older version of Haskell was used.

I was very surprised that Compojure did not score higher in the rankings. I have several deployed apps with Compojure and it seems very performant.