I think a lot of people thrown by the styling were expecting more of an Mk1 GT40 shape. When I first saw pictures I scratched my head a little bit, especially over the cars proportions. Then this dawned on me:
The road-going Mk3 GT40 suffered from the same issue. Clearly part of the GT40 bloodline but oddly proportioned. Compared to the Mk1/Mk2 the Mk3 looks "too long" due to lengthened rear and front overhangs as well as elongated headlights. Looking at the '05/'06 GT next to the '17 GT yields the same effect, for me at least. As Ford has moved away from full-blown retro with the Mustang, I wonder if the new GT took some subtle queues from the Mk3 as a way of evolving GT as a whole.