You seem to say that only Mr Roddenberry authorize change. He didn't own Trek, however.Once is a clarification. Twice smacks of ego. (Three or more times, you're just being ridiculous...)
The DSC Klingon look was doable in 1979, with the resources and budget of the time. If Gene wanted them to look like that then, he could have done it.
Unfortunately, Gene is dead and has been for quite some time. The decision is out of his hands. It is up to the show runners to decide the visual aesthetic.
As far as violating canon, the Disc Klingons are canon, like it or not. Canon is the body of produced Star Trek. So anything that is officially produced with the Star Trek name is canon. The argument is for continuity and not canon.
I don't like the redesign, but, like @Greg Cox, I've been a fan for decades and I don't find the changes in aesthetic contradictory. Different times, different tastes. We all don't like change.
But, change is inevitable.