I think this is a long way before the dust settles. Today we view video on everything from something as large as a side of a building down to a watch-size screen.
Guys, to be clear, I'm not talking about letterboxing here. I'm not talking about seeing a theatrical property in the same aspect in which it was shown in the theater. I'm talking about old TV shows being cropped to fit 16:9. Are you still so worried about that? Do you even care?
Is there a perfect size? An eye scientists could probably answer that
And then just when you think you know the perfect size screen, 3D or even a more advance hologram takes over.
I doubt anybody will ever be 100% right on this subject.