I get a ton of value out of having my shell history available (both for search but also to try to reconstruct steps of what I did yesterday when my memory is hazy)

I guess you could set up an entropy scanner and flag history lines that have high entropy, but that might not be enough (low-entropy secrets) and might be bothersome (lots of false positives / things that are technically secrets but that you don't care if they're in your shell history).