I dont think the war in the pacific becomes boring, it becomes non-existant for the allies. However, as you said, with Germany asscendant in Europe by turn 4, it becomes crucial for the allies that the British and Anzac forces from the Pacific, be allowed to move to Africa, the Middle East, and, eventually maybe, Europe, to help the mother country. Similarly, With the Axis in Europe growing to such a powerful state, the USA will need to focus most, if not all, of its IPC welth to save Europe and liberate the UK, should London fall to the Germans. With all of Westerm Europe and the British home isles under German control, their economy will be around 50icp before NO’s, and with 2 of those the will be at near 60, I think. If you combine that with an Italy that controls the Med, middle east, and neraly all of Africa, you have a second power that will, once NO’s are added, be at around 40ipcs. This means the USA will have more than enough to do in Europe, and not having to fight in the Pacific will be a decisive.
Japan will also have more than enough to do trying to fend off the Soviet Union and the Chinese. Granted, at first Japan will be able to crush most, if not all opposition in the area. However, once Soviet units start to arrive in China, things will start to swing against Japan. And as more of the Soviet offensive forces reach Siberia and China, it will become harder for Japan. Also, and this may be where Japan will have the most trouble, its economic gains will not be enough to sustain a protracted campagin of attration against the Sino-Soviet forces. Japan has 2 great strenghts, its airforces and its navy. While it is extreamly unlikely that the Soviets will ever become a threat to the Japanese navy, it will, over several turns, be able to reach parity to the Japanese in strenght of airforces, through both attrition and through dedicated spending. The problem for Japan becomes that the only places it can expand to increase its economy is into British and American tt to their south, even to get NO money as well. However doing so, in the face of a determined Soviet offensive and a passive German east-front, is suicide for Japan. Therefore, a Japanese player that finds itself in such a situation must fight with considerable skill and tatical wisdom if its going to stop the Sino-Soviet forces arrayed against it.
Dosnt sound like a very boring war to me! :-D