I am not sure that a mirrorless camera inside a bulky DSLR body using DSLR lenses is what Canon (and Nikon) need. They will have to introduce the new mount and a whole new range of lenses that require shorter flange distance in order to make their bodies and lenses more compact and competitive. Otherwise Panasonic, Olympus and Fuji will eat them alive. A big advantage of a mirrorless system is more compact lenses that allow better IQ for the same manufacturing costs, if done properly. Look at Fuji - their APS-C lenses are already better than anything Canon or Nikon can offer for their cropped cameras. Switching to a mirrorless range effectively means for Canon/Nikon killing their DSLR cameras AND LENSES, and probably that is why they are hesitating.