First of all, one thing you gotta accept when talking about stuff like this is that the reporting is pretty much always contradictory, subjective, speculative, vague, biased, and often just flat-out incorrect.
Second of all, saying that "elements were produced using the original camera negative" means almost nothing. Almost ALL major restorations are, in one way or another, derived from the OCN. That doesn't mean there aren't a bunch of pointless generations between the OCN and the release print. On top of that, Nolan became involved in the project after WB had already gone back to the OCN. He wasn't a part of that stage.
Here's where the problems begin:
Mr. Price and Mr. Nolan began by making duplicate negatives
Immediately, from phase one of Nolan's "unrestoration," they are working one generation removed from the OCN. This removes fine detail. It's unavoidable. It's not only completely unnecessary to ultimately strike release prints from elements so far removed from the OCN - it's absolutely mindboggling. Soooooo much fine detail has been lost by the time it hits projectors.
Here's another problem:
a complex method of color correction. This process required some imagining of what Kubrick would want, with prompting from the faded source material.
Color correction is, of course, a part of restoring a film. Has to be done. But Nolan saying there isn't any potential revisionism here is just wrong. The goal, usually, is to get as close to the source as possible, but interpretation is involved at this stage. And this is often molded by contemporary grading trends and - when you have someone like Nolan involved - his own biases. (Speaking of modern trends, raised blacks is another one Nolan loves, and I'm terrified of seeing that in 2001, a film which is full of the deep black of space.)
And his own movies look like shit. He has proven time and time again that he has no idea about how to properly present a film for home video release, let alone an "unrestoration" for projection prints.
Also, that goddamn word. "Unrestored." It's completely meaningless, and betrays just how little Nolan actually knows about what a "restoration" is. He acts like restoring a film is what George Lucas did when he created the OT Special Editions or something. Just utter cluelessness.
And here's one last little kicker:
Christopher Nolan is red-green colorblind. It's mystifying that he would be allowed to have a hand in color correcting 2001 with that knowledge in mind.