Auto magnify is a good idea but I suspect that the Canon lenses do not tell the body when the ring is being turned so it would be hard to implement.
For anybody with an EOS M or other mirrorless camera who like to use manual focus, the best solution I found on my 4/3 camera is to put the camera in B&W mode and max out the in-camera settings for contrast and sharpness. This makes it a little easier to identify what is in focus on the screen and if you shoot in Raw the settings are not permanent.
The new lenses need to report distance for the hybrid autofocus to work properly.
Good tip about contrast though!