Hi Jeremy. Dmitry's argument you mention, for instance, is questionable and not very popular. I think I can't point to what you're going against (vs "old style" coding), maybe some examples in the post could help.
On CS: you are already using a compile step that dynamically changes code, how more complex can it get? I have thousands of lines of CS in production and it never caused any more problems than JS. If you think of CoffeeScript as a tool to write Javascript, not a separate language, things go much smoother (you want to debug the javascript output, not the cs source).