Yeah, it's definitely something I'm hoping the CA/B Forum will address at some point. Something like a month seems like a sweet spot between not being annoying for new customers when they're in the process of getting multiple certs and not being a huge deal when domains are transferred.

I'm not aware of any kind of "Authorization Transparency" effort. Let's Encrypt were thinking about a way to share logs at some point (IIRC), so it might get included in those, but that's a maybe for the future and not a general solution for all CAs.