1. The various considerations you mentioned was the reason why we did not go to Baghadad in the last gulf war. Saddam should have gotten a hint and become productive member in the global system. Sadly he has proved himself otherwise. The uncertainties that you have raised can not compared to the danger posed by a Saddam with nuclear weapons.
2. I do tend to have a relatively agnostic and pragmatic philosophy. If productivity is not the ultimate test, how exactly do we settle my-god-beats-your-god disputes? By litigation?