A year or two really isn't a long time for a beta of this nature.

Personally I agree. It’s a social engineering feature and, accordingly, you need a lot of time to see how the system ends up abusing/adapting/repurposing it.

It’s just an easy critique: “they don’t ship fast enough according to my totally uninformed and arbitrary assessment!”

I think even 2021 is late for such a critical feature. It should have been thought of and implemented even earlier. If Twitter can maintain an army of bluecheck mark verifiers, reversing bad community notes could be handed over to them or similar group of people, especially when Twitter's aim was to be goto source of quality information.