To me, working with Strongtalk felt like it was a specialized form of SUnit testing. For instance, one of the options in Strongtalk is to perform some form of type validation on a class (and I think there were several levels of checking available). This to me felt like running an SUnit test suite.
And, as I've said before, I think the typing should be optional for both the writer and the reader (meaning that any attempt to do this in Squeak should take into consideration that even though the author of a method may have included type annotations, the reader may not want to see them).
My feeling is that the sweet spot for typing will fall somewhere between the Strongtalk system and SUnit testing.
- Stephen