I'm also hoping that the pixels aren't all split in a left/right horizontal pattern, as the video shows, but that half of them are split vertically, because no one would want the AF system to be sensitive to horizontal contrast only.
Based on what I've read, including a statement from Chuck Westfall who was asked for clarification on the matter, they are all split in the same direction. That means the Dual Pixel CMOS phase AF system is a giant vertical line sensor, responsive only to horizontally-oriented details.
Any guess as to whether the next generation will have a quad split (2x2) to do both vertical and horizontal or would it be better to use the next neighboring pixel of of the same color instead?
What they might be able to do is to have a pattern on the sensor of PDAF cells rather than just straight up and down.
So maybe the new bayer sensor looks like this:
I = vertical AF sensor and one for horizontal might look like this:
- = horizontally sensitive AF sensor.
Or they might do:
but to subdivide all of the pixels again would really cut into the ability of a pixel to capture light for recording the image with.