I think the answer that Miyamoto should have given was that the focus of Star Fox Zero is innovation with the gamepad, not so much graphics. If the two-screen concept really works then the gamer is going to be so busy focusing on the dual screen gameplay that they won't have time to focus on the graphics, anyways.
I honestly found that Mario Kart 8's amazing graphics are largely wasted since the gamer doesn't have time to even notice much of the detail. That's going to be even more the case in an on-rails shooter like Star Fox Zero where the gamer has not one but two screens to worry about.
I am honestly much more worried about the two-screen concept being awkward or unnatural for the gamer.







