Sure, there's always some statistical distribution in any manufacturing (within SPC and specification limits) but as said in the review: "But I think you’d agree in real photographs it will probably be impossible to see the difference"
No I don't agree. I had a copy of the old 24-70mm and it was on the low end of that chart. Very soft and eventually I got rid of it. I don't think it is acceptable to pay $2300 for a lens and to take a lens that is on the lower end of the performance chart.
Some people are reporting fall off on the 70mm end. There are a few things that I would expect of this lens. I would expect that it performs at least close to my 70-200mm f/2.8L II at 70mm. I would expect that the new 24-70 would meet or exceed the sharpness of my 35mm L and 24mm L at f/2.8.
While its true most photographers would never know if the lens they bought is lacking. I would know on my copy, for $2300 I expect the highest level of quality control and performance.