Currently, the module reading function requires the selected module to have the same data structure as the default (historical) module. The game should have a function to selectively read the default module and then selectively replace data from the selected module if they existed.
For example, a fantasy module may have its own troop preset, but everything else is the same as the historical module. Then the game only needs to use troop preset from the fantasy module and use other data from the default module.
Currently, the module reading function requires the selected module to have the same data structure as the default (historical) module. The game should have a function to selectively read the default module and then selectively replace data from the selected module if they existed.
For example, a fantasy module may have its own troop preset, but everything else is the same as the historical module. Then the game only needs to use troop preset from the fantasy module and use other data from the default module.
This should reduce data redundancy by a lot.