The impossible AI is supposed to earn more money and have more design points to spend. It is not more clever when it comes to strategical considerations.
Perhaps there is something wrong with those settings.
BTW check old score graphs if you can see how much the AI:s were fighting (provinces going up and down without your interaction).
The AI do not wage war on humans on purpose. They choose between both human and AI players (very democratic of the AI
). This means that you might attack an AI while he is attacking another AI. It is often not too difficult to attack enemies (in SP or in MP) that are unaware and weakened by other wars.
If you have a game where you have won easily zip it and send it over. Please refrain from sending over games that seems OK. The files needed are the ftherland file and the trn files.