Historically time zones were the purview of cities. (Often it was the banks and/or churches in a city coordinating time for that city and its relation to solar noon.) It's why the IANA preferred timezone identifiers are cities like America/New_York, America/Mexico_City, Europe/Berlin, etc. Go back far enough in the IANA timezone database (which is used for all sorts of things on the internet and in general computing today) and you'll find all sorts of interesting historic timezone offsets for cities. Some not even to a round offset like 30 minutes, but to single minute or even fractional minute (seconds, milliseconds) offsets from UTC.
I don't know if a return to per-city offsets is the best idea. Software could handle a lot of the messy details for us in ways that the railroads could not have taken advantage of with only so much space for physical clocks. But a return to per-city offsets isn't really the worst idea either if we are looking at what problems Daylight Saving Time was supposed to solve and didn't solve very well.
It'd be most convenient for local events, but maybe not for non-local events.
I'd open my bar at the most eastern point.