If he favors type safety and switching between modules of different type systems, Racket already has that, doesn't it?
Generally though, I think Haskell's approach of re-adding freedoms is more fruitful than trying to add bondage to Lisp. And "the Haskell movement" certainly has a different kind of manpower behind it.
Can you clarify what you mean by the words "movement" and "different kind of manpower"?
How is progress in languages like Racket different from Haskell?
Why do you think that adding "interesting" type systems in Lisp would be "heroic" and less "fruitful"?
First, i don't think associating innovativity with numbers of researchers is a safe predicate since it's clearly not linear.
Second, the fact that haskell is a testbed for researchers doesn't make it the ideal language for "real world programming" in my opinion. It could be that it is, but again the correlation is less than clear.
And third, and that's the most important point in my opinion, the ideas developped in haskell are fully available to other language implementors once they exist, and the experience of researchers is available. It means that a language like typed racket or any other could possibly implement the best/most usefull of those ideas in much less time than was needed to first find them.
Once upon a time Lisp was a language for researchers.
That's the price of freedom of Lisp.