Whilst we're going to have to wait a month to find out what the distortion is like on the 16-35/f4L, the MTF graphs and samples tend to suggest it is going to be a class leading lens. And how long have we had to wait for it?!
And if Canon can do that, can it finally deliver a FF sensor that is also class leading? By class leading, I'm referring to noise control and DR that is close to linear right through the ISO range and that matches or exceeds that of Sony sensors.
What's important about it being linear? At the moment Canon sensors have a DR function that is flat in the low ISO range as opposed to Sony's which is linear: below ISO 200 (or is it 400?) there is very little gain in DR from Canon sensors whereas Sony's deliver substantial gains the lower the ISO goes. I suspect that prior to Sony's sensors coming out, people thought that the "flat area" at the start of Canon's graphs looked good because there was no degradation. What people didn't realise is that there shouldn't be any flat spots, rather the DR (colour, noise, etc) response of the sensor should be close to having a linear relationship with ISO.
You do realize that the 5D3 1DX and 70D sensors are better than anything Sonikon makes in several categories right? Just because those aren't your favorite categories doesn't make them any worse.