Of course Canon can improve. That's not the point. Every company can improve on some things, including Canon. I don't praise everything Canon all the time, so you must have mistaken me for someone else. I don't care for the EOS M's autofocus. I wish that Canon offered mirrorless cameras similar to the A7, X100S, X-Pro1 and EM-1. I wish the 5D3 had AF points that light up properly. I wish the latest firmware update didn't introduce a problem with flash. I wish they made a better 50/1.4 & 50/1.8. If I thought long and hard, I might find a few other things to criticize. None of them is a big deal for me.
My statements are only controversial in the sense that they go counter to the complaints of a few anonymous people on the internet who seem to make very problematic photos (banding, shadow noise, limited DR, etc.) and blame them on Canon's technology. Ardent critics of Canon's sensors are typically anonymous people whose credibility can't be assessed. Such critics promote the idea that their technical problems would be solved if only Canon did something like some competitor, and yet such critics don't seem to have the sense to solve their problems by buying the products of that competitor.
My statements reflect my personal satisfaction with the current state of Canon's technology. And they are supported by many other photographers choosing Canon despite Canon not ranking highest on some chart on a testing site. Canon may not be "class leading" on some technical parameter, but there are plenty of excellent, talented, knowledgeable, non-anonymous, even "class leading" photographers who choose Canon over competitors.
We are starting to converge in our opinions :-). I agree that every company has strengths and weaknesses and I agree with your Canon wish-list.
We still differ in that you refuse to acknowledge that Canon sensors need improvement. If you just argue against the extreme opinions of a few Canon haters, I have no objection. However, you seem to indicate that Canon sensors are great the way they are. It may not be important to you, but other people wish for better IQ in the 70D, for example. While dual pixel AF is a great feature, the IQ apparently has not really improved compared to the old sensor from years ago. Landscape photographers may wish for more resolution and DR on their FF cameras. These expectations are not unreasonable, if the competition was able to deliver on them.
These points are more or less general consensus rather than just complaints of a few anonymous people. True, distinguished photographers don't waste their time critisizing Canon sensors, but neither do they sing accolades - because they are too busy shooting :-). That does not mean that they are perfectly happy with these sensors and do not wish for improvements. As long as the sensor is not so bad as to be a dealbreaker, people would continue choosing Canon products for other reasons. Some great photographers may use the 50/1.4 - and yet you yourself admit that it could be better. Similarly, the fact that great photographers use Canon sensors does not mean that the sensor problem does not exist. More so, the sensor that particularly needs IQ improvement is the APS-C sized one, which is less frequently used by the pros.
I believe that the problematic photos you mentioned are simply used to emphasize and demonstrate the problem, just like a brick wall photo is used to evaluate distortion and does not represent the photographer's actual art.
I also agree with you that Canon can't and needn't top every chart on every testing site. On the other hand, when after years of stagnation, their APS-C sensor is outperformed by almost every other company's sensor and even by the smaller MFT sensors, I find that frustrating.