What I am expecting is the larger than previous mount (Z > F) will facilitate the design and use of 0.95 lenses. I remember some rumours around that, not sure from where, there is so much stuff going around... I suppose that will qualify as a "new dimension"? Or it could simply be that this "new dimension" is just a qualification of the new Z mount being larger than the F mount?
Doesn't exactly sound like a great justification for a much larger mount. f/0.95 or f/1.0 lenses would be a tiny proportion of usage and lens sales. Even if these could be made a bit smaller by using a wider throat, the wider throat would necessitate making
every other lens larger to accommodate it - not exactly a good tradeoff when the bread and butter lenses are the f/2.8 zooms, f/1.4-2.0 primes and, for a small subset of fast action cameras, the superteles. Anything faster really belongs in the niche area of oddball artistic lenses rather than the category of general working lenses.
Besides, Leica has made f/0.95 and f/1.0 lenses for the 44mm M-mount, Nikon has made f/1.2 lenses for the 44mm F-mount and Canon made f/1.0 lenses for the 47mm FD mount. And Nikon and now Sony have both made fast superteles (400mm f/2.
compatible with throat diameters in that range. You can use the Noctilux on an E-mount camera with no optical problems, and you can also use a Canon 400/2.8 or 600/4.0 lens (both designed for much wider throat diameters) on EF-M or E-mount with no optical problems.
EF-M and E-mount's 46mm is actually quite middle-of-the-road for 24x36mm-format lenses - some lens mounts designed for 35mm film had throat diameters as small as 39mm (although these obviously couldn't take telecentric lenses), while some designed for 6x6 film (56x56mm) were as narrow as 57mm. And many of these mounts were designed and made before digital, before high ISO, before fast film, when superfast lenses actually were a necessity just to prevent motion blur. Really, it's Canon's EF mount which is the anomaly here, not F-mount, M-mount or E-mount, which are all in the same ballpark.
I'm not saying there's no justification for a larger throat - just that fast lenses are unlikely to be the reason, unless Nikon has decided to move into a niche market rather than primarily targeting their bread-and-butter audience.