"He also said that there's no mechanism to compensate for the absence of duck typing. In Haskell, at least, there are type classes which allow you to make your types as duck as you would wish, maybe slightly less."

I think that type classes are the way to go.

Duck typing is mostly popular because multiple inheritance sucks, and because inherting a class to only overload a method sucks.

Languages like Ruby, Python or Perl are so popular because they are less verbose than Java or C++, with the disadvantage, that the compiler can't help you that much.

Haskell is a language that combines the advantages, less verbosity with a helping compiler, and a static type system that rocks.