[Shadowstar]

It seems AI's will research war technologies even when they are focusing on exploration/colonization, but won't actually build any war ships to take advantage of thier advances until they actually go into attack state -- even if they're being attacked. There should be something in the code that ensures that the AI's will start building up-to-date warships when they get attacked, if they aren't already.

How about letting the AI's go to attack state based on thier personality traits and whether they have explored systems belonging to a nearby empire that is relatively small and would be an easy target (based on available information). Obviously, peaceful AI's wouldn't attack at all unless they were being attacked but the agressive ones would naturally want to focus on weaker empires, and the really agressive ones would prioritize this over exploration at the earliest opportunity.