The shape of a wearer's wrist matters as much - if not more - than its circumference.
It's fascinating how much attention is given to the case diameter, lug-to-lug length, and the shape and drop of the lugs, as though these are the defining factors. While sometimes the colour of the dial and its thickness are also mentioned, we don't consider how the shape of one's wrist is an equally important physical determinant.
Someone else in this thread brought up a crucial point: the shape of the wearer's wrist. Does a wearer have a round wrist with a small surface area where the watch will sit? Or does the person have a obloid-shaped wrist with a broad surface area under the watch case? A person with a 6.5" wrist will have a very different experience depending on the actual shape of his/her wrist.
A more general point: we now fetishise case diameter to an unhelpful extent. Just look at the collective meltdowns when Rolex announced the proportions of the new Sub. People were having fits without even seeing the watch in person, let alone wearing one (unsurprisingly, these apprehensions have now been put to rest as they had no sound basis). Lesson? The obsession with measurement is one sure way to erode the pleasure of wearing watches.
This pleasure, lest we forget, derives from physical experience where a millimetre here or millimetre there doesn't matter. Whether I'm wear my 35mm vintage Omega or a brand new 42mm Parmigiani Fleurier on my approx. 7" / 178mm wrist, it's the watch in its physical totality that matters, its aesthetics, symbolism and meaning, and how all these things make me feel.