

The AI does not suicide into the line as often and instead is more likely to conduct more careful attacks along side large tank pushes.
Adjusts production priorities in the AI. Instead of spamming ♥♥♥♥ infantry, they'll instead focus much of their production on tank divisions and air planes.
HOI4 AI always were utterly terrible at building airplanes. As long as you built meta fighters and had the industry to back it up you'd basically always win. Well not anymore. The AI will built meta fighters to destroy your nation in the air.
The AI will build good ship designs, so naval battles are no longer free.
The AI will waste a lot less civs and instead focus on building a massive industry for you to face off against. You won't be able to out build the AI with your eyes closed.
Instead of building an army of 16w divisions with two light tanks, the AI will instead build beafy medium tank divisions and even heavy tanks if it has the industry to do so.
The AI will build AT in their divisions and use it against you. Your tanks will not automatically roll through enemy infantry.
Forces the AI to research key technologies if they don't for a long enough time period. You will no longer be fighting Fighter ones in 1941.
The AI will now have five different AI: Postures, which are viewable strategies the AI takes depending on the situation it finds itself in.