Old civilizations need to be more differentiated.Savar and Legionary are good ideas, I suggest more unique units as replacements to common units, for example:
1.



crossbowman renamed to heavy crossbowman, Cost increased to 30 wood / 50 gold.
Gain +1/2/3 bonus vs cav unit & infantry unit, Attack speed changed from 2.0 to 2.5,gain +1/2/3 Armor while stop moving.





pikeman renamed to heavy pikeman, Cost increased to 35 food / 35 wood, gain +1 range, move speed decreased to 0.9.



camel rider renamed to camel Raider, Cost increased to 75 food / 60 gold, reduces the damage of nearby enemy Cavalry units by 20%.


spearman renamed to Poisoned Javelin Thrower, Cost increased to 35 food / 35 wood, spears will inflict an extra damage over time effect with their arrows, dealing 3 damage over 6 seconds.





Militia Line units renamed to shield warrior, Cost increased to 60 food / 30gold,
can “dodge” 0/0/1/2/3 consecutive projectiles in a 20 second time frame, gain +1/2/3/3/3 vs trash units.



scout line renamed to Steppe raider, Cost increased to 80 food / 20 wood, gain +1/2/3 vs range unit.

