This setup seems as god as it gets for 3D planes where lots of throw is needed. As for IMAC, not an advantage IMO. Since most can't afford to have one plane for freestyle and one for sequence flying, I think the setup should appeal lots af poeple. I explain :

If a standard setup gives 60 degrees of surface movement and 60 degrees of servo movement then the direct drive system is as good if not better since the aforementioned advantages.

If a standard setup gives 20 degrees of surface movement and 60 degrees of servo movement (like in IMAC only planes) then the direct drive system is not better as the standard setup offers MUCH more resolution.