The "trend" you talk about is a lot less prevelant than is often described. You see a lot of still pictures posted here of the racket face closed 30 degrees, 45 degrees, even more, after the hit.
Those are mishits. The ball hitting below center is tilting the top edge forward.
What the video shows is something different. The vast majority of the hits are still with the racket at 90 degrees or very close. Some are definitely tilted--usually super high bouncing heavy incoming balls.
According to Rod Cross there is a formula for a certain height, racket speed, racket tilt, etc that will work and I believe him.
But the tilts I see are in the 5 to 15 degree range. Never seen those same huge angles as in the still photos--unless of course it's a mishit...