The verbosity of Java isn't necessary in all statically-typed languages. For instance Haskell is no more verbose than, say, Python, and has an even more expressive static type system than Java.
I didn't mean to imply that the verbosity/complexity of their original code base was caused by the type system. The article is light on details, so we can only speculate: maybe they'd be better off with Haskell but just failed to consider it, or maybe they considered all options and decided it would be easier to retrain their team and integrate with the existing code based if they used a JVM Lisp. What is clear is that they have a much smaller and more maintainable code base now than they had before, and so they're better off than they were.
