I think the GP's point is that there is something mediocre about common sense. I think it's similar to the most beautiful faces being also (very close to) the m

I think the GP's point is that there is something mediocre about common sense. I think it's similar to the most beautiful faces being also (very close to) the most average ones. "Mediocre" is not a good word for this concept, it implies a scale. Maybe Turing test for intelligence is "wrong" exactly for that reason. It's like a test of beauty based on human faces. Maybe we need to accept that just like there are two different standards of beauty (i.e. face one, in which humans will always excel by being average humans, and the other, beauty in its own right, way e.g. fractals or Bach's music are beautiful), there are also two standards of intelligence, which are named in the article as "mediocre" and "excellent". Maybe it would be better to call them "human-like" and "brilliant".