Pacific General greatly builds upon the AI offered in the earlier 5-star general games. The largest improvement is the AIís ability to wage land war.
In earlier games in this series, AI units tended to be completely reactionary. In fact, the coding of the AI has units that do not move until an enemy has been spotted within range. Until then, they sit dormant. For example, in the Warsaw scenario in Panzer General, there is a Polish city near the starting German location.
If you drive around the city and never make contact with the infantry there, that unit will never move. However, if you happen to fly an airplane by, it will activate and begin marching towards the German VP starting location. Essentially, units never really take the initiative to launch counter-attacks.
Pacific General, on the other hand, utilizes its units. The AI will conduct local counter-attacks often and repeatedly. This makes the battles more realistic as you have to guard your flanks or your offensive will stall. This creates a deeper strategic element as you have to balance your drive towards Victory Locations with protecting your gains and support units.
Another problem from earlier games is an AI that is afraid to lose troops. In the Vyazmy scenario
in Allied General, the Russian player starts with a large block of units supported by artillery and anti-aircraft units. The AI will not attack this group if it is tightly defended with the supporting fire, since the calculated odds are against their favor. Sadly, the AI does not recognize that they need to sacrifice troops to wear down fortified positions. In fact, they will park units along this front and essentially never attack, wasting those units as it attempts to drive around the fortified area looking for attacks with a better chance to succeed.
Pacific General shows a willingness to throw units at you, especially when playing countries known for having large amounts of cheap units. Itís really the only effective way to wear down heavily fortified positions.
Overall, Pacific General is the smartest AI in the 5-Star General series. If you wanted to Mod any of these games to create your own units and scenarios, this would be the one to start with. Also, if you look around for the Pacific General Armory on the internet, you will find a lot of good resources for doing just that.