@Bee:
I agree very much. Miscommunication between the commanders has a lot to do with the worsening relationship I mentioned above.
However, we should note that individual battles are not very important in this war, at least not if we consider alternate scenarios: Given the tactic options, battles only took place if both armies sought it, or one army was caught by surprise. If there was enough time, one of the armies could easily fortify in the field. So the attacker would have to switch from assault to siege, which usually required more perseverance than the armies had.
This explains why there were so relatively few battles for such a long war.
Most of the decisive events in the war were the occupations of cities, and the marauding in the countryside.