I think there is a genuine concern that Canon sensors are no long competitive and are a generation or two behind Sony and Nikon (same sensor). There is some minor gripping about this and that feature or mirroless offerings but the real complaint is the sensor. When Canon had the best sensors (a long run) the Nikon fan sites were awash with similar complaints on their sites and the fanboys saying things like "12MP is all you ever need". Same thing you are seeing now on this site. The fanboys are saying things like "18MP is all you need". "I would never buy a camera with than many mega pixels", or "It's the glass, yeah, thats why I stay with Canon" ignoring the fact that Nikon has equally fine glass and Sony shooters have access to better stuff. If Canon catches up the same old fanboys will be lining up to buy the best stuff and crowing about how important the big sensors are.