Fujifilm proudly declared they would not be going with a 35mm sensor size in the future, for one, believing that it's a bit redundant since they currently cover APS-C and cropped medium format. There are significant benefits to both formats: the former covers a Super35 area and is currently fast enough for excellent video capabilities that consumer level 35mm cameras are currently unable to match, while medium format has a level of detail and low light capability that exceeds all current 35mm format sensors.