I'm assuming you already compared(hand-on) your primes Vs 24-70 f2.8 II?Yes, I did - with my hands and my eyes. 24-70 II is sharp @ F3.5. But, 85/1.4, 135/2, 200/2 are far better @ F2.8 than 24-70 II @ F2.8.
How do you recomp....f1.2 lens at 1.2? not saying you can't with crop in pp
I do not recompose with any lens, because the right moment of a shot is lost and sometimes correct focus is lost too.
24-70 II can only reach up to 70mmm and you compared to 85, 135, and 200mm?
What I'm seeing in my 24-70 II is extremely sharp at f2.8....I haven't shoot at f3.5 or smaller yet.
Pic below was taken inside a pre-school classroom. I cropped nearly 70%, no flash of course @ f2.8. You have any pic at f3.5 on your 24-70?