I have colleagues at institutions who teach LISP-like languages (Scheme, Racket) to incoming first-year students. They name the same benefits you do, and trust me, I am onboard for functional programming as a first PL generally. But I am curious whether you know how successful your program was in "outreach". Our CS1 course uses Python, and students implement a game (inspired by Pokemon). They find it very exciting, and for a lot of them, the "computer very literally does what you say" is a revelation to them. I would worry about losing some of that switching to Haskell. I'm not saying that it's an impossibility. The main obstacle in my department would be that only a handful of the faculty even know more than a few languages.