I finally managed to find some data from anthropometric tables for wrist sizes. It makes it all the more difficult to understand the dimensions that watches are getting to. Average male wrist circumference is 6.79" (172.5 mm) with a S.D. of 0.19" (4.8 mm).
I thought I had teeny wrists, but it turns out I am above average and there is no way any watch over 42mm looks remotely sensible on me. I'm not "unused to the size," I own and enjoy one watch at 41.5 mm. It's usually a problem with the lugs hanging over the sides of my wrist on some of the designs! Take AMVOX1 for example, it fits me at 42mm precisely because of the clever lug shape.
Of course, there is no objective, consistent and quantifiable position on the case size topic - it depends on the case design, proportions, and the wrist itself not just circumference, BUT also its shape, width, thickness, and fleshy boneyness.
But I think it is a pity that most manufacturers replace their watches for larger alternatives. There is really no good reason why watches have got bigger except for fashion. Another thing is changing the perception of what looks small and what looks big.
When is big too big? Well, I don’t mean to suggest that watches shouldn't be over 42 mm. Certainly even a 46mm dia watch I saw on Stallone the other day is almost too small for him.
However, in light of the data above, I find it unusual that manufacturers and designers would target their designs to mostly fit (and I use the word advisedly) above average wrists. This must naturally reduce sales as the target number of consumers compatible is lower, but in today's market place it is often form over function for many, many products. But as someone said, "A man with pants too short looks silly no matter how tall or short he is."
Let people have their fun; in the end, if people want to buy, with their own money, 60mm let them. When they get tired of it, so will the manufacturers to fill that demand.