IMHO the correct way to handle leap seconds would have been at the same layer as timezones, i.e. a display-only thing. Timezone databases are regularly updated, you push out leap second updates there. In the worst case, people's clocks are off by one second but all the underlying timing logic doesn't crash.
I fully expect in such a regime, people would be complaining about how the leap second insertion caused their recurring meeting to shift from 9am to 8:59:59
you can use TAI (international atomic time, basically UTC without leap seconds) if you want to be serious about it
I'm a fan but it's rare for anyone else to agree!