Is raider strength linked to population, town centre tier level or game year etc. I posted this on steam and best guess is population number.
I’d say Pop, Tier, and difficulty are the obvious answers
In addition to population and tier, it also feels like it’s related to your gold reserves. More gold in the bank seems to attract more raids
I upgraded my town hall to Tier 3 and started getting raiders who could kill my soldiers, who were equipped with heavy weapons. Where as before even with up to 10000 in the bank my soldiers mowed through them with ease.