I've got an S4 and Samsung Gear S3.. honestly the round face looks much better and the information is presented beautifully so I'm not sure if you're talking from experience or theory, but there'd no question it sounds like to a lot of people at least, round would be a nice change or addition.Traditional watches were round because of the fixed length of hands.
Most every display not dependent upon mechanical hands is not circular because when displaying information a circular cuts off useful real estate.
Books and newspapers have a portrait format for the same reason.
There’s a reason TV’s evolved from round to landscape shapes.
Round on the wrist was a confining format suited to unflexible and feature limited mechanical devices.
Why burden modern information display with an outdated and inappropriate format? (Yes other brands use round but this is largely for differentiation as it confers no performance benefit.)
Even the apple logo would look better at start up