Correct, no game will ever be perfect. Nothing, in fact, will ever be perfect. However, I have never asked for perfection, so that whole argument is out the window.
As I have said many times, creating a great AI is the primary challenge to a strategy game designer. They must strive to make the AI as competent as possible, with the aim of making your challenge in EU resemble as closely as possible the challenge presented to the actual leaders of the country you are playing. However, this should ideally be done without giving the AI any special advantages or allowing the AI to cheat. This is a tough challenge for the designer. I will stipulate that perhaps EU has done the best job of doing this of any game ever made. Nevertheless, of all the parts of EU that I have witnessed, this emerges as the greatest weakness. Perhaps this is because the game is so superb in every other respect.