From the video "The biggest benefit here appears to be for people with Full HD screens"
This is what a lot of us have been saying and expecting...I think Sony is underplaying the benefit to plain old full HD 1080p, there's still oodles to improve at that resolution rather than jumping to 4K. I only miss HDR.
I know you will love BF1 on PS4 Pro. Titanfall 2 is also very good by all accounts. I can't tell you if you'll love it or not though, without the kind of prior experience like you have between BF4-BF1.
Don't see any reason why people would think it was impossible. You can checkerboard from anything, they just prefer to do it from 2x1080 than anything else as it provides the cleanest image. If its only going with a lower resolution for a few seconds you're not going to notice as much compared to the frame dips.
Temporal reconstruction where the size of the frame is changing seems like it could get complicated as far as I understand it. Maybe if it doesn't change that often they can just start over every time it changes? I am very curious about what they're doing.
Even watching it on compressed youtube the PC 4k native is night and day. Would be interesting to compare 1440p native upscaled on PC to PS4 Pro checkerboard. It's a very soft image on Pro as noted in the video narration despite the resolution construction.
With Titanfall 2 at 900-1000p and BF1 the same on PS4, TF2 shows a decent leap using standard 1440p upscaled on Pro