There is a huge exploit when trading with A.I.
A.I. will happily trade all of his empire (except for his homeworld) for a hefty amount of credits per turn.
So as of patch 1.01, you can easily win any game by just buying everything from A.I. and then declaring a war (therefore breaking your promise to pay) and killing him with his own ships, while not loosing a single credit. Same goes for offering trading and luxury resources. In my opinion, A.I. should not give anything immediate for Something-Per-Turn. At least, not without Non-Aggression pact for the duration of the deal in effect. Sorry if this is a known issue.