"it seems that generally the SACD layer is only slightly more resolving"
Good point.
I have not heard about what you have mentioned, neither here, or anywhere else. It may be more resolving, but not enough to make an audible difference.
I do have two CDP`s on my rack. One, is the Rega Saturn, prior gen. and the other, a Yamaha S2000 SACD player. I have found, that, the Saturn sounds more detailed. But, it may be that the Yamaha is a warmer sounding player.