I've also been asking some questions of my local GHC internals guru BenLippmeier. A couple of open questions Ben brought are as follows:
* The paper seems to be based on the System Fw + algebraic data types
(including existentials) based core, while core is now System Fc
with equality constraints and coercions. How does that affect this
project?
* Does anyone have any feel for whether the Core2Core transforms will
be easier or more difficult to write with Strict Core?