It is possible to control both the number of key shares and the threshold required to unseal Vault (and now to do automatic unseal too), so I’m not certain this particular condition should be too much of a concern anymore. That said, considering as many scenarios as possible is definitely sensible!

I really do not understand your frustration. We are running 5 node cluster in production with the keepalived and nobody needs to wake up unsealing if one, or two instances fail. Perfectly good to do it in the morning by copy pasting curl oneliner from the keepass.