Better accuracy of altitude measuring equipment and pressure to increase capacity, that's the story and I think by itself there is nothing wrong with it.
But I have a question on turbulence.
Is turbulence behind heavy aircraft, with a tendency to slowly drop but staying persistent for quite a few minutes, a problem for the lighther categories of aircraft flying thousand feet below on the same precision track?
The expected advent of light jets able to fly up till FL410 may aggravate the problem.
What does one think?