really interesting post.. I dont think that revenge caused this war though.. If they had revenge in their mind then probably krishna wud not have sent a sort of reconciliation proposal to duryodhana before war..it was more of war of justice after he refused to even offer 5 villages to pandavas.. i think there were lot of other factors that attributed to war.. and not just draupadi's insult.. others who got involved also had their personal agenda with Shikhandi getting involved for Bheeshma's deed..dristdhumya getting involved for his own father's insult revenge... then there were other kings who joined each side owing to their own agendas... This War then became a War of justice.. though i agreed with your perspective that this War was more destructive in its nature and thus does bring in question..was it really necessary..? To that.. I have somewhat more a philosphical view...it is said that earth needs to shed its negativity when it exceeds .. then it somehow finds it way to do so..
Draupadi's insult became one of the many reasons of war but it wasnt only reason ..
regarding Krishna's involvement in War, I feel he was the central hero in the epic.. he kind of guided pandavas to victory..to establish the fact that justice prevails..and unjust is punished...