The problem is believability from the headset as well as motion sensors.
First off, the approach of the occulas headset is the same approach as any other in terms of screen placement and such. In order to make believable VR, you first need to have enough wrap around to allow you to get most or all of your peripheral vision involved, as this will give you spatial awareness as well as help you determine depth. Second you need approximately 50 degrees of overlap between the screens as this is about what the normal persons vision is capable of. Again this will help with believability as it will add depth to the image.
As far as the resolution, I have not tested nor am I anywhere near financially capable of testing, but from what I have read, the need for full HD for the displays isn't really there as they can make things look pretty good on the lower res screens. The reason is because of how close they are to the eyes.
The problem I can foresee about all this is how well these will work for people that require glasses. Some are near sighted and some are far sighted and others just need glasses for reading. How will this effect the persons ability to get a clear image from a VR headset?
The only solution that I can think of would be to have custom ground lenses made that are placed ahead of the screens and this would be rather expensive to make.
