Since KM creates a version when the Editor is started, and when a Revert is requested, why not create a version of "Latest Version Before any Reverts Today", or even create a date/time stamped version before you execute a Revert request?
The more you rely on the user to do something manually in a critical process the more likely there will be a problem. Reverting is not something a user needs to do very often, so even if they know today to restart the KM Editor first, in a few months or years they may not remember.
The KM Wiki is woefully inadequate in finding and explaining how to use "Revert Macros". It is buried in the "Menus" page. Also, I think that many users might not ever think of "revert" when they want to restore the previous version of a macro. I know I never would have searched for "revert".
Revert Macros Section of Menus Page -- KM Wiki
The Revert Macros menu in the File menu lets you revert to a previous version of your macros. If you find you have really messed up your macros, you can restore your macros to a backup version of how they were when you first launched Keyboard Maestro, or how they were yesterday or even several days ago.
Seems like we need a Wiki page dedicated to this very important feature. I would title it "Restore (Revert) All Macros to a Prior Version"