At this point in time, I doubt there will ever be a square chip, but I'd like to make a case why square was so useful during film days. If you were a commercial photographer, shooting for clients, (clients that many times change their minds), and say you were shooting for an ad that was roughly vertical 8.5x11. Say that ad was to run in multiple publications. Say that that ad would change sizes slightly, depending on the size and format of each publication, thus forcing this ad to be "repurposed" as they say, for each publication.
So you have this one image that you shot, that will now be used in five different sized ads. And as we all know, most photographers like to fill the frame, and compose appropriately.
If you'd shot the job on a square Hassie, the AD would simply recrop the image for each magazine, and there would be TONS of extra room on the sides, to go get more image. There'd never be that dreaded phone call at 4:59pm, (before you left on another job the next day), saying, "Uh, is there any more image on the side of this frame? Uh, could you clone some?" Or, in those days, the phone call would be more like, "Uh, we had to order an expensive dye transfer print, and then hire a retoucher to build in bleed, because you shot the image so tight". And then he'd hang up, pissed.
So, with FF 645, things are relatively OK, but with this Leaf crop, (or Canon/Nikon crop), I'm all the time feeling this "squeeze" when you're shooting vertical. You fill the vertical part appropriately, but then there's not enough extra frame on the side, so then, you scoot back, and then there's this voice in your head saying, "Jesus, there's way too much dead space above the guy's head".
In short, 2x3 proportion = Bad News for a commercial photographer.
Again, who are these companies consulting with in advance? Only weekend-warrior landscape photographers?