I recall that Hasselblad showed a square format concept camera at the last Photokina, the V1D. I think it contemplated the use of the XCD lenses and the current "true" MF sensor with 100MP in a square format to yield 75 MP. Will it show up at Photokina 2018? I doubt Hasselblad has the bandwith to pull it off.
It looked the part, and it featured in one of the LuLa videos with a Hassy head honcho - unless I am getting confused again. However, it remained on the desk and nobody pretended it worked!
Using lenses optimised for larger formats on smaller formats is not an ideal situation at all, as I discovered years ago on film. I agree with those who would suggest that 1 x 1.5 does not make for a perfect format: it seems to work well for horizontals but less so on verticals, especially with people.
Using crops within a camera is not something I would want to do - I think my Nikons allow that but I have never wanted to use the feature. The only time it was done (by me) was with film, when I made masks for the viewfinder for specific jobs, and that was very rarely indeed.
I'm one of those people who makes the framing suit the format. Yes, of course one can take a straight FF shot and then make sub-framings within it, but why? Better get it right first time.