The world has been a terrible place for a long time, and will most probably remain so for a long time to come. A sad situation, but one that can't really be remedied by war. Especially a world war. A world war on disease? A war on the gap between rich and poor (hard as the top two money industries are oil and weapons, and usually the poor are the ones who end up on the front lines)... And war as a way of controlling population?!?
But really, look at the world after the previous world wars, did it improve the world? Or did a lot of people suffer, then suffer some more and then where here and now....