Ok I've decided to make these changes so far, any original untyped stats are unchanged.
Units -
Ballista Elephant - 1-2 first strikes.
Camel Archer - 2 first strikes, 9

, 80

.
Gallic Warrior + Swordsman - 7

Jaguar - 6

, 30

Preatorian - 40

Holkan, Spearman, Impi - 30

Hwacha 6

, +25% vs melee
Landsknecht - 8

, +50% vs melee, + 50% vs mounted.
Longbowman - 40

Numidian Cavalry - 6

, +25% vs melee
Quecha - 25

Vulture - +35% vs melee (50% was too strong, 25% too weak).
Buildings -
Assembly Plant - 2 free engineers, no engineer slots.
Baray - +3

Forum - 120

, +50%

production
Mall - +50%

Mint - +25%

Pavilion - +50%

Research Institute - +50%

, +1 free scientist, no scientist slots.
Salon - +1 free scientist, +2

Seowon - +40%

, +4

Stele - +2

, +50%

Stock Exchange - +75%

, 1 free Merchant.
Also trait changes -
Industrious - double production speed of Forge, Factory, Assembly Plant
Organised - double production speed of Lighthouse, Courthouse, Recycling Centre
Protective - double production speed of Walls, Castle, Security Bureau, Intelligence Agency.
I also wanted to add +25%

to Protective, but I have no idea how to do that.