Version History for Modules and Content Definitions
Content and Module definitions do not always stay the same forever, and the ability to track changes on these items would be incredibly useful just like the same feature is incredibly useful for Page and Content items with Agility.
Also, within Agility there is the real possibility of breaking production servers by accidently removing key content definitions/modules or through removing fields from definitions.
The ability to roll back between versions and have a history of changes for these definitions would be invaluable.
To give an example of what it could prevent:
After copying a module, I edited the incorrect one changing all its fields. There was no way to roll back, or to see what the old fields were outside of inspecting the already implemented APIs within #C code.
Providing change management to the most sensitive and fragile part of AgilityCMS would be a great feature.