Alexandre doesn't want an approach that requires the custom compiler in upstream Wine, so we'll presumably eventually need another approach. I think he basically wants to reduce the non-PE surface area far enough that it becomes feasible to manually write thunks at the PE/host interface.
I hope that answers your question.
Yes it does, thank you! Another option would be to auto-generate the thunks through usage of libclang, that would be better than handwritten, IMHO.
Regards, Fabian Maurer