I have a small ideas.
1- Ability to toggle garrisons to field archers or infantry
2- Or a research that changes 40% of the garrison to archers, if it deploy 4. 2 infantry 2 archers. if it deploy 5, 3 infantry 2 archers.
3- The Garrisons reflect their nations unique units like, Roman Garrison deploy legionary, Japanese Garrison deploy samurai and same for stables Greeks companions, French their unique cavalry.
Maybe without the unique status to keep the defense balance (think more of it as a cosmetic look change)
1- Ability to toggle garrisons to field archers or infantry
2- Or a research that changes 40% of the garrison to archers, if it deploy 4. 2 infantry 2 archers. if it deploy 5, 3 infantry 2 archers.
3- The Garrisons reflect their nations unique units like, Roman Garrison deploy legionary, Japanese Garrison deploy samurai and same for stables Greeks companions, French their unique cavalry.
Maybe without the unique status to keep the defense balance (think more of it as a cosmetic look change)