I think this type of question is emblematic of the situation that Adobe has on their hands with Catalyst. If it is the one app that gets content produced in a CS app to the Flash platform, why stop at PS, AI, FW, etc... why not allow content in from ID, AE, etc?
Some of the promo material make it seem as though anyone can produce a basic RIA with FC, and so, it seems as though they have opened the door for this dicussion. Encore is a bit of a similiar beast to FC in some ways, taking CS app output, putting it in an interactive IDE to author content for output in a format that is esoteric to many (MXML for FC, DVD authoring spec for Encore).
That said, simply thinking that because it's an Adobe app it should be able to produce FXG for consumption by FC is probably a bit of wishful thinking that many Adobe users are transposing over to their favorite Adobe apps whether it be Encore, Director, Captivate or {insert Adobe app here}.
