One time zone? It doesn't have to stop there. Once you've disconnected local time from solar time, there's no reason for keeping to a 24-hour day. If you made the day a bit shorter, there'd be more working days per year in which to get things done. OTOH if you lengthened the day by about 21 minutes, you'd have a nice round 360 days per year, 12 months of 30 days each, no leap years to mess with. A 9-day week (add Uranus and Neptune to the list of Sun, Moon and 5 naked-eye planets) would tie dates to the same weekday each year.

The only drawback is that moveable feasts tied to a lunar calendar, such as Chinese New Year and Easter, would be even more moveable...