[JJ_SO]

It would be interesting to learn about the reasons for the various ratios. I think, sometimes it was just availability of manufacturing machinery and a lot of coincidence involved.

However, a squarish sensor would indeed demand some redesign of sensors, LCD (!) and EVF first and then it could lead to hardware with not only interchangeable lenses, but also - you mentioned Fuji, Klaus - to better, tiltable EVF. Exchangeable sensors, maybe. Kind of Hasselblad/Rolleiflex style (Zenza Bronica I don't know much about).

But this hasn't happened during the past ¼ of a century, Victor Hasselblad is dead and todays brands fight with other troubles...