Well I'll be, I stand corrected. It works and it is beautiful.
This changes things. With mods that only change RootTemplates (that we know of so far), it is possible to:
1) Merge multiple RootTemplate mods into a single mod that is used by the game
2) Effectively uninstall the mod from a save-file by over-writing its MetaData with an un-modded save MetaData
3) Install the mod into an *existing* game-save, so that the change can be implemented without restarting the campaign. Again this is done by over-writing the MetaData of the existing save with one from a new game that has the mod enabled.
We need to make a tutorial on this.