I know 1Password 4 is not even in beta yet, but I was wondering.
Many developers have implemented a system where there apps can detect the presence of a previous App Store license and use it in lieu of entering a key for those who wish to transition to a developers site version. Many of those developers also no longer sell in the app store so it may be a stop gap measure for them I don't know.
Without going into technical details and all is this a possibility for 1Password ? I am on the fence, but thinking no due to your current presence in the store and the technical reasons like Apple not sharing much information with you etc.
Anyway I just happened to think about it.