True, and that's where it feels like the Haskell side would be powerful. I did a small demo app with Yesod and loved it, and we have a ton of state machine type

True, and that's where it feels like the Haskell side would be powerful. I did a small demo app with Yesod and loved it, and we have a ton of state machine type logic that would hugely benefit from ADTs. You're right the hybrid approach seems better, but there it seems more like that Python/Ruby with their new gradual typing seems like the way to go, adding strong on top of dynamic rather than trying to poke a hole in strong typing to let you be dynamic.