I have to say, I really don't. The way you're talking, I could create a 35mm f/0.95 and run sandpaper over the front element as part of the finishing process and you'd choose it over any other lens because OMG THE DOF. Do you only ever shoot wide open?
Another example that's a bit more real world is the Canon 85mm f/1.2 vs the Sigma 85mm f/1.4. The Sigma is in every way the better lens except for that f/0.2 difference - you'd have to be beyond obsessed with ultra ultra minimal DoF differences to throw away every other benefit and spend quite significantly more money on an inferior lens just because of that aperture.
I guess you've got your priorities and I have mine and we might as well leave it there
Actually, I did pick the Canon 85/1.2 over the Sigma and even though now I have the Sony 85/1.4 GM, and by all metric bar the 1.2…I prefer the look from the Canon. You mention feel, and there is something about that 85L that feels right.
Aperture is the main priority for me, it really is, not just about the look, it’s simply more light coming in. 1.4 is 1.4 from a light gathering point of view, the T-Stop will no doubt be higher but a F/1.4 won’t have a T-Stop of 2.8.
No system is perfect, and we have our priorities, wide aperture is the top of mine. Having a wide aperture also give you more control and flexibility, I might not shoot wide open all the time (I do a heck of a lot…probably 90% of the time), but having that flexibility to is important.
I learn this like the hard way a while ago when I shot film, and then reminded why again when I first got the Fuji x-Mount because I went and bought the 24 and 35 f/2.0 lenses, thinking….these will be fine, they are small…but the inability to go wider to under 2.0 really bugged me, I traded both for the 1.4 lenses within a month.
I know what I like and what my priorities are when come to buying lenses, and the GFX don’t have what I want, unfortunately. All but 2 of the lenses they make would be what I would get, but the equivalent 35mm one isn’t one of them.
It is one of the reason I switched from Canon DSLR to Sony, Canon still, after all these years on the R mount, don’t make a R mount 35/1.4.
When I say dealbreaker, I mean it. There is no exception for a 35/1.4 for me as it’s my favourite focal length.