I suppose the personalities are intended to reveal themselves more gradually. I've tried to reproduce that through WorldBuilder and saw some extra Archers but no big stacks – but you wrote that it doesn't happen very frequently, so that doesn't say much. I would surmise that large numbers of Archers are only trained during war preparations (you could check by holding down Alt while hovering over the scoreboard in cheat/debug mode). If so, then discouraging early AI war plans should solve the problem. To that end, I'd try increasing UWAI_WEIGHT_FAIR_PLAY in AI_Variables_GlobalDefines.xml; perhaps from 100 to 150 would be enough. That weight affects the first 100 turns (speed-adjusted). Will also affect e.g. Axeman rushes of course. Giving Archer a NotUnitAI "UNITAI_ATTACK_CITY" could also help. Pending evidence to the contrary, I'm assuming that this is mostly not an issue in the base mod – though it's not clear to me why it's happening in your mod, that is, unless starting locations are very crowded.