As long as it's not like earlier versions of HOI3, where the UK would automatically declare war on Germany in January of '40 if Germany hadn't done anything to start a war on its own, the diplomatic system has to be an improvement.
It should be set up so that war is in Germany's best interests, because the ongoing trade restrictions are leading to economic stagnation, and the rapid military expansion for war is something that can't be sustained in the long run without looting another country's treasury and/or resource stockpile (which is really difficult now that both currency and resource stockpiles have been removed). If Germany can continue to build up at an unrealistic rate, then it doesn't place the historical limits on Germany. If Germany can't make an early surge in rearming for war, then it doesn't make for a very interesting game when Germany gets crushed quickly without much of a struggle. The new mechanics using national focuses seem like an odd way of balancing things.