So many issues, like having to relearn the clock when you are in another timezone. I’ll meet you for lunch at 06.00! Life is based around the sun.
Having some sort of agreed upon world timezone would be neat though, whether that was GMT or something less euro centric. So everyone would understand “we have a zoom meeting at 11.00 WT” instead of having to decide which timezone to refer to.
There is only one good alternative, which would be to place the date change line in the middle of the Atlantic (between UTC-3 and UTC-2) and the fundamental time zone in Japan or somewhere Australia (UTC+9/UTC+10).
Greenland is probably the best reason to keep Greenwich as the reference time zone. :) Most of the population (so to speak) is on -13 to -12. I have no idea if the people there have more ties to continental Europe and Iceland, or to Labrador.
Don't we already have that with UTC / Zulu time?
I usually see Americans treat Eastern Time as a standard, with references to Pacific sometimes. In the EU, where I am, CET is the usual timezone used for specifying a time internationally. And regardless of the location, it's very common for people to specify a time in their local timezone first and leave it to the other party to figure out what the difference is.
I haven't encountered situations like someone saying "let's have a discussion at 16:00 UTC" to set up an EU-US meeting.
My colleagues and I do this, but we're often involving 3, 4, 5+ timezones. Everyone knows their own offset from UTC, but I easily forgot whether Australia is on DST this month.
So whenever I specify a time with someone that could be in a different timezone, I would either make sure that I am using some application that solves it for me, or I would AT LEAST include the timezone.
Maybe I'm just not encountering the same problems that you do.