Something I noticed reading it: why do they recommend the f4 lens for crop sensors, and the f2.8 lens for full frame? Why not recommend them more situationally, like, use the f4 lens when distance hiking and climbing or when you want a lighter set up, and the f2.8 lens when low light or out of focus back grounds are desired?
I have a 7d mkii and a 5d mk iv. I use my 70-200 2.8 on them both. On the 7d, the 70-200 lens serves admirably for bird photography if the birds are close. The extra stop helps a lot. I would feel deeply the loss of the stop on the edge of day and dark, or during big storms, the sort of times when birds often come out (like those elusive rails......). Anyways....
Also, what is the new coating?
In general, I am rather excited about this, I will totally get the new f2.8 lens, in likely 7 years, when I can justify and afford the upgrade expense...