Actually, I see having to rework the type schema when the requirements change as a plus, not as a con. In a static language the compiler can point out all the b

Actually, I see having to rework the type schema when the requirements change as a plus, not as a con. In a static language the compiler can point out all the bits of the program that need to be updated to conform to the new schema while in a dynamic language this kind of stuff is usually only detected at runtime.