I had to refactor viibee's internal structure of how we handle locations and was so glad that ActionScript is statically typed. Otherwise, I would have freaked. So, to my surprise, I must confess that I like statically typed languages.
Duck typing may be the latest craze, but right now I do wonder why it sometimes works so well.
Maybe it works OK in Rails because the amount of code one writes is typically less (so refactoring by hand is usually doable) and the structure is given (so you know where to look), plus you can use tests, of course. I guess in Rails the feedback one can get from tests and quickly running the app is almost as quick as what my Flex compiler tells me.