Sure, it would be nice to have a valid, relative ranking for each tested lens to help with decision making. But how can you know how closely their criteria resemble your criteria?
If you have the time and own some of the cameras and lenses that DXO have used for their tests, you could verify the results for yourself, making allowances for minor variations in lens quality control.
For example, I own a D800E, D700 and the 3 lenses shown in the DXO test results above, in my reply #10.
What I find fascinating is that the P-Mpix of the medium quality Nikkor 24-120/F4 zoom, when used on the 36mp D800, is about the same as the P-Mpix ratings for the excellent 85mm and 35mm primes when those lenses are used on a 12mp full-frame camera.
Now I don't have my D700 with me at present, just the D800E and the D7100, so I'm unable to carry out such tests for myself. However, what I would expect to find is that the zoom set at 35mm and 85mm, used on the D800E, would provide a very similar image quality to those primes used on the 12mp D700, when such lenses are used at their sharpest apertures, and the D800 images are downsampled to 12mp.
If this were to be correct, it would be useful information for those who may already be satisfied with the pixel count of their camera but who would like to upgrade their lenses. Instead of buying a few expensive primes to use with one's D700, one could just buy a D800 and continue using the 24-120 zoom on the new camera. If one doesn't need 36mp, no problem, just downsample the images to 12mp and get the image quality of a first rate prime used on the old camera.
The primes may always have the advantage of a wider aperture, but the zoom has, in many circumstances, the more significant advantages of flexibility of focal length range and image stabilization.