IMO, Weapons Upgrade from Ancient Ruins is unrealistic and a bit unbalanced. I think it should be changed, so:
One of my most easiest games was the one in which I was playing with the mongols. I remember being in the middle age with 2 cavalries, due to keshik being promoted through ancient ruins weapon upgrade. As you can imagine, enemy cities were falling very quickly, thanks to cavalry/keshik/khan extra mobility and cavalry strength (instead of horseman).
- It maintains the current behaviour only if you have the required technology. For example, a warrior would be upgraded to spearman only if you have researched Bronze Working.
- The unit receives extra XP if you don't have the required technology. A warrior would receive extra XP instead of being upgraded to spearman if you haven't researched Bronze Working.
One of my most easiest games was the one in which I was playing with the mongols. I remember being in the middle age with 2 cavalries, due to keshik being promoted through ancient ruins weapon upgrade. As you can imagine, enemy cities were falling very quickly, thanks to cavalry/keshik/khan extra mobility and cavalry strength (instead of horseman).