IP I have both and played them muliple times. It is hard as the Japanese to win in the Pacific. North Africa is a total lost cause. The Rules do add a wide variety of options to play, SS Panzers, Paratroopers, Destroyers, Sub Pens.
I have over the years incorportated all the playing pieces into my Axis and Allies so I do not play them any more.
Both games are fairly balanced. World at war you can play the Poles, Italians, Greeks, Turks, Spanish, Hungarins, French, Dutch and Scandanavia with the first addition and and extra playing pieces Xeno provided. Quality of playing peices are not equal to the MB AA first genration game.
Hope this helps.
WARRIOR888