@dopp : nah, that would stop the AI from invading, ever. cannot_force_invade is the "sit down, shut up, read a book or sumtink" AI function :)
Right now I've merely disabled all raids except when the factions are already at war (I figure a weak faction wouldn't want to draw too much attention anyway), and removed the "don't care for factions we don't share a border with, want peace" factor since it is obvious now that they *do* care, even though I don't understand how and why :)
But first the antitrait thingamajig, then X-mas derailed my tests, and now my comp itself is acting up (fan problems, overheating, BSOD's, the works...). Patience :)

@Vladimir : sure, but Jinettes cost a mint to produce and upkeep, while x-bows are cheap.
Anyway, I do agree with you, but that's not something I can mod directly, what the AI does with a given order is all hardcoded as far as I know, we can just fiddle with the orders themselves, and the descr_strat army preferences :/
And in any case, unless you really know what you're doing, sending a weak force against a big stack will not result in a weaker big stack, but only a dead weak force. The more lopsided the odds, the less losses for the big guy, unless you're all about HAs. Thus, given that the AI cannot handle raids properly (I can't tell it to only use HAs or skirmishers for raids, it just uses troop cost from what I can see. The AI seems to assume a 300 florins unit will beat a 200 florins one, period), I think it's better to do away with them alltogether...