The images look pretty sharp!
However please supply proper 100% crops so we can take judge!
Should be easy to do.
Could we have a moon shot or two as well with/without 1.4xTC when weather conditions are right.
I suspect these latest very expensive long lenses from Canon are "birder" lenses designed for max sharpness at close range - say 50Xfocal length ie not exceptionally sharp at infinity - say 300 metres and beyond.
Just click on the image and click on it after it has loaded and you will get pretty much 100%. These files are very large JPGs so determining IQ from them is a fair assessment.
In my experience lenses that are very sharp up close are very sharp far away. As long as you are shooting with a calibrated AFMA you can expect the same IQ across the distance range. The limiting factors are not the glass, but rather less pixel density across your subject and more atmospheric factors to contend with.
I agree, it would sure be nice to see more test images, and of subjects shot at a variety of distances and not only birds but mammals, people, brick buildings.... etc...