No, it is a change that breaks everybody using UTC correctly, TAI with a offset to synchronize with UT1, in order to fix everybody who did not know what they were doing and used UTC when they actually wanted TAI.
If there was a scheme that fixed only the wrong usages, that would be fine. But, it is frankly absurd that we should even consider breaking carefully designed programs correctly using their dependencies to fix programs incorrectly using their dependencies especially when it is trivial for the wrong usages to be fixed manually.
No, UTC is TAI kept in sync with UT1. Changing UTC to being TAI with a offset is a fundamental breaking change in what it means. Anybody relying on UTC doing what it is designed and advertised to do, keep in sync with UT1, will be broken. The only people who will not be broken are people using UTC incorrectly as TAI. The only reason this is interesting is that basically everybody uses UTC incorrectly as TAI, but that is not a valid excuse to break the programs using it correctly.
People using the wrong dependency should fix their system to use the right dependency. They should not campaign to steal the name and replace it, that is absurd.
Literally nobody depends on any relationship between UTC and overhead sun angle.
The only people who care or need to do not use UTC. They use TAI, and a separate continuous log of fractional seconds.
UTC has one role, and that is Standard worldwide civil time. Telling people who need Standard civil time to use TAI makes everything strictly worse: not only do you then not match most of the world, but you still have to track irregular, unpredictable corrections to be able to sync with everybody else.
Except that standard civil time cares about the overhead sun angle for some reason, that is why we use the day demarcations of UT1 instead of TAI. If we really decided as a society that we really no longer care, then we should switch standard civil time to TAI and do away with UTC entirely, not calcify it as some arbitrary offset from TAI.
> "cares about the overhead sun angle for some reason"
That is what is proposed to be fixed and that you are arguing against for reasons you don't know or, apparently, care about.
Switching civil time to TAI would break everything, most of which cannot be fixed. Random breakage is the problem. More breakage would be strictly worse.
Well we could introduce negative leap seconds until they align. The problem (UT1 deviating from UTC by more than one second) would be the same as in this proposal.
> Literally nobody depends on any relationship between UTC and overhead sun angle.
That's just... completely incorrect and totally false? Have you ever even worked for a business? Have you ever read how time libraries are actually written?
It is literally built on the exact assumption that 0 means January 1, 1970 and that right now is (number of seconds in a day) x (number of days since Jan 1 1970). If we stop adjusting UTC, then by this time next year UTC will be one second out of date with our wall-clock times, and calling `datetime.now().isoformat()` will give us a timestamp that's 1 second off from the wall-time of a user. At one-second past midnight on the 20th of the month, your computer will incorrectly be spitting out timestamps saying it's exactly midnight of the 19th. That's what you might call a major breaking change.
If there was a scheme that fixed only the wrong usages, that would be fine. But, it is frankly absurd that we should even consider breaking carefully designed programs correctly using their dependencies to fix programs incorrectly using their dependencies especially when it is trivial for the wrong usages to be fixed manually.