Hickey does insinuate in several talks that false dichotomy of static vs open, so that's worth criticizing, but I don't think that's anywhere near the core of what "Maybe Not".

Also some people are saying "[but he's talking about contracts, and type systems are an entirely different beast]".

I'm sticking my chin out and saying that they're not entirely different beasts. Contracts are runtime and static types are compile-time, but Hickey is pointing straight at one form of static typing, then at another, then saying "[our contracts should be like that one, that's more expressive and more useful]".