Here's an example of a deeply toned coin that I think meets Doug's comment and would be considered a tad too dark for many a collector. I guess it also slipped by the PCGS graders!
Catbert that is one I would love to see in hand. You can still see the luster in some places through the dark toning.
...but there are going to be a lot of unhappy collectors out there 20 years from now who collected all of these "perfect" coins and find that they have various and unpredictable forms of toning.
Yeah, probably some. But there will be others who are happy about it. Besides, 20 years from now most of the original owners won't even own the coins anymore.