Uh what? Exactly what in the display tech do you think they could not have improved? Are you saying that 4k phone displays don't exist? Are you saying they could not have used these in the HMD's? Are you saying there is a GPU that can push two 4k screens with AA and all the lighting effects of modern engines at 90+ fps?
On the Lenses, they seem perfectly fine to me. If I take off the foam on my vive, my FOV is huge as well as my sweet spot for focus. What is not ok when I do this is the display res, its even more noticable.