Timeline

I think one thing i would like to see is a proper timeline of events, including the formations, rises, and falls of various kingdoms since the War Against the Fallen, as well as various actions taken by the Church of God Awaiting to control those nations, such as efforts to carefully prune kingdoms that were moving beyond their control, at least until Charis successfully pulled it off, and subtly removing rulers and monarchs that didn't meet the Church's needs or requirements.

We've been told about the Treaty of Silk Town, but while a full and proper timeline would be nice to have, I can't see the Author taking time to write one. Indeed, until he needs to fix some past event in stone to serve as the foundation for some current event, he probably doesn't want to do so as it would limit his options. The best we can likely expect along those lines is if by some chance a Safehold RPG were to be created, but even then the RPG timeline would never be canon the way the books are.