I'm looking at the ISO 6400 example between all three camera, and I see virtually no difference. Although, if I may say so, in some areas the 7D looks sharper than the 70D, but there are a variety of factors to consider. In some areas, the lighting or reflections are not exactly the same, so that can skew the results.
Thinking about it though, since the megapixels have increased in the 70D, the image quality has had to improve to some degree to keep up with the 60D and 7D.
Next, I looked at the ISO 100 example between the 70D and 7D, and saw virtually no difference either. Maybe in some cases some of the colors were better in the 70D, but that's really just clutching at straws.
Both the 7D and 70D appear to provide the same image quality is what I'm seeing.