Spartans have a further limit on their champions which have excellent stats already. It does not have to be a hard limit, one idea is to have it as a percentage of current population. we actually did the opposite. There is no restriction on their champs… yes they are strong…. But champs can’t gather resources to produce more champs  you can only train 3 helots per every champ…. Although you can train up to 10 without. i dont know how to do a percentage of population….. we also have it so spartiates take longer and longer to train as you phase up and tech up. So you need to mix in more helots and Perioikoi 

In one of our versions we had a bonus where CS for Brit’s/gauls and more HP. Cause where they bigger/fiercer in stature say compared to the Romans?  maybe I’m just thinking too much American dramatized Vikings on TV  but could do something similar if it could fit for the tribes. All melee + 25 health or something.

Well I removed it for Sparta… but their military techs are a little stronger than the average, so by the time you get p3 full techs, they are still fully capable of fighting without it.  For example we could start with city states -10% pop bonus. + 10% infantry attack (none of them really had great cavalry) no will to fight tech. although I still think if give Sparta a little something to be a little stronger at least infantry wise. Unfortunately we have touched the navy and almost never play on water maps. That should definitely be Athens strength over Sparta.

One other idea: Spartans were very wary of foreigners and heavily restricted their entry into their lands. In fact, they thought foreign influence would corrupt their youth. Maybe restrict their ability to trade as well as their allies' ability to trade with them? I also remember reading they used iron ingots rather than coins of precious metals as currency, but it sounds a bit like a myth. One thing is certain though: not a lot of Spartan coins are found in archeology. Another reason to penalize trade? What's on your mind 

Yeah, actually we renamed it hoplite reforms. and I am now OK with the the of them getting the -10% pop bonus… even though Athens was maybe 2 to 3 times the size of Thebes… all 3 were by far the smallest of the 16 factions. Also I like maybe none of them having Will to fight, but stronger militiaty techs or something?