The leading contender is a trade NO that gives Japan 10 IPCs per turn that it's not at war with France, UK/ANZAC and/or US.
germany and italy will not have a declaration of war(dow) on usa until turn 4 as there is no incentive for them to do so. this leaves only japan to gain from a turn 1, 2, or 3 dow.
with alpha setup a j1 dow never happens. usually it is a j3 dow with the rare j2 or usa3 dow.
with this 8ipc(no walking into 2ipc french indo china) incentive it will always be a j3 or usa3 dow every game.
not only does this change reduce variability(one of the great ideas of this game is how different round dows give the game a different playout) it does nothing to address the usa spending all ipc in one theater this is the real culprit in the game being unbalanced.