The player Omnius started a thread about the games' AI, characterizing it as ignorant. It should be noted that Omnius is an inveterate game hater, loves to tear down, rather than encourage. Just look at his history of posts on Matrix, when he takes a particular disliking to a game.
In fact the WoN AI can be quite challenging when given the proper startup settings (as Zakblood clearly pointed out in Omnius' thread), and when the player doesn't set out to exploit every failure of the AI.
Play realistically, and the AI will be fun. A recent example for me was the Sealion campaign, which I've played as both the French and later as the British. In both cases the AI had valid strategies and moves. I did not play beyond 1806 in either case, but plan to do so in the future to see how it goes for the AI.
In a longer playthrough, I may end up doing something that adds to the greatness of the game - the player can at any time play a turn or two for a country normally controlled by the AI - to correct an army org problem, and such. Then continue with the AI controlling those countries.
Enjoy the massive depth of the game without nit-picking the occasional errant AI move.