[zuppy]

Why redesign the watches? This problem doesn't exist in the places that use the 24h format (like most of the world around North America). We can use both time formats. I can either say 9 in the evening or 21 and everybody gets it.

[swombat]

Because "9 in the evening" doesn't mean much when you're a quarter of the world from GMT and forced to use GMT as your universal time.