Why not a 21.6mm x 21.6mm sensor?

Rather a modern Hasselblad! (I'm a swede). I think a square sensor is a nice idea, and a square format. 4/3 is so close to 1/1 anyway. The sensor corners could be a little bit outside the image circle but not that big as 21,6x21,6. You could choose between square, portrait and landscape afterwards instead of turning the camera 45 degrees. Or choose format with a button on the camera. Like you could with the film APS format, if someone remember that.