Monads are important, but I don't think it's fair to call them the "crux" of Haskell programming
That may be overstating things a little, I agree. On the other hand, a programming language that can't model ordering of events along some sort of timeline isn't useful for many practical applications, and monads have so far proven to be the most effective way of introducing those concepts into Haskell's naturally timeless environment. They're also absurdly overcomplicated for modelling simple but not trivial cases, relative to just writing the code in the order you want things to happen in an imperative language. So if the goal is to get more people to use Haskell to write useful software, I would expect a lot of emphasis on monads and related concepts.
That may be overstating things a little, I agree. On the other hand, a programming language that can't model ordering of events along some sort of timeline isn't useful for many practical applications, and monads have so far proven to be the most effective way of introducing those concepts into Haskell's naturally timeless environment. They're also absurdly overcomplicated for modelling simple but not trivial cases, relative to just writing the code in the order you want things to happen in an imperative language. So if the goal is to get more people to use Haskell to write useful software, I would expect a lot of emphasis on monads and related concepts.