Yeah, I think it's tricky to know how most sysadmins could make good decisions about this information, especially when misissuance is likely to be less than 1% of 1% of all CA issuance and automated renewal is working properly. Warning fatigue is a pretty big deal here!
Also, we made Certbot randomize the subject key by default every time it renews, so you have a huge amount of churn in subject keys, so you can't just say "oh, well, this public key has been used for a long time, so it's probably correct!". Every subject key is typically new and is unrelated to every previous subject key.
I hope that won't turn out to have been a poor trade-off. (We thought it was good to have more turnover of keys in order to reduce the impact of successfully stealing or cryptographically attacking one.)
