As a sportsshooter, I must say that if the RATE button and the button above it is what a think they are. Those two buttons really scream sportsphotography workflow.
My guess is that the RATE button replaces the LOCK button find on the 1D series. By pushing the button once you will lock the picture and giving it a 1 star rating, by pushing the button again (on the same image) you will give it a 2 star rating and so on.
The button above is probably an "in- camera" crop button or image edit button.
Both these buttons would really benefit workflow for sportsphotographers.
The lock button on the 1D series is often used to do a first rough selection "in-camera" You then choose to only download the selected (locked) images from the CF card to the computer. By doing this you save time and speed up workflow.
A rate button would give me a chance to do a more narrow selection in camera. In game action portraits of players would , for example get a one star rating, while more time critical images of goal celebration, injuries would get a higher rating
A crop button would let me crop pictures in the camera while the game play is away from me, that way a don´t need to do it in the computer which saves me time. Also a very
good feature if shooting live.
What really puzzles me is that if this new camera is a high megapixel/low speed camera aimed more at studio / Landscape, why prioritize these two buttons? Or do other non-sportphotographers also benefit and se these buttons as a useful workflow feature?