First of all, Germany lost the war by a huge margin so nothing would have changed the outcome.

Like basically all dictatorships, there had to be some sort of balance of power in Germany. Hitler tried to divide power on the lower levels as much as possible, ensuring that no single faction would be powerful enough to challenge his status. Germany, essentially, had two separate general staffs, fighting two separate wars. First, there was the 'Oberkommando des Heeres', responsible for the more important theatre, first Poland, then France, and finally the Soviet Union. In addition, there was the 'Oberkommando der Wehrmacht' which was supposed to organize the less important theatres which for Germany meant the Western Front once the invasion of the Soviet Union had begun. Not too surprisingly, having two separate high commands creates unnecessary friction and lower efficiency. By the way, Japan faced the same problem as the Japanese Army and Navy were basically fighting two separate wars against China and the Western Allies.

Similarly, Germany had created two separate Armies, first the more conservative Wehrmacht which followed the tradition of the Imperial German Army and the Waffen-SS which was more devoted to Hitler. Cooperation between these two branches often proved difficult too.

Within the German navy, there were two strong disagreeing faction, one that preferred a strong submarine force and one that favoured more capital ships. This argument was never clearly decided before the war and, as Germany lacked the necessary resources to build both a strong submarine force and capital ships, the German navy was weak in both regards early in the war.