............Fast lenses with NF cameras with only center AF focus points have limited ..........
............Full length fashion for example where you want the eyes in focus.............
In practice I believe your 100% wrong.
This week I've been shooting thousands of full length fashion vertical frames with a third of them focus and recompose, many more with a single center point focus.
In our quick overview (we're still in production) only a very small percentage are not in focus.
(In a couple of months when the project clears embargo I may show them).
It's rare photographers shoot full length fashion wide open, 1.8, 2.8 or whatever. Most client's don't want just the eyelashes in focus they also want the garments which is their product in focus, regardless if it's editorial or for commerce.
I've probably shot a few fashion images at wide open on any camera.
Focus is never really easy, regardless of camera and even cameras with multi point focus, usually one point is more accurate than another.
The best focusing camera I've used is our Canon 1dx, better than our Nikons, but still not perfect.
No camera is perfect, all are different nearly all professional cameras today are very good.
I really don't understand why anyone compares them.
In fact the most famous 35mm cameras of all time were designed around focus and recompose . . . the leica.
Since you mention eyelashes in focus, well . . .
I shot this in Paris, almost wide open with an M-8 series using window light and practicals, by focus and recompose.
It was almost wide open because it was just a fun snap, when the model was still in hair and makeup.
Also, one center point focus is also not near the end of the world, as you suggest.
This image was with my Contax 645/Phase p30+ focusing with weak modeling lights on the subject, strong in the lens lights poking through the background to flare into the lense and the subject moving fairly quick.
I don't think one from this session was soft.
If my old Contax will do this, I can promise you a Phase DF/ Mamiya, A h4-5d, a Pentax will do it sleeping.
But here's a hint. If you really want to have sharp images and pixel peep until your eyes bleed, I suggest using a tripod.
Nothing improves sharpness like a tripod.
BTW: For someone who reports time and time again on the results of their medium format experience, by drawing charts and designing pulsating gifs, didn't you test your DF before you bought it.
If you dealt with a professional dealer, that's not difficult to do, before you actually spend the money and find yourself suffering buyers remorse.