The Empire, Utopia and Power

In thinking about the world today and all of the petty wars and civil strife taking place all over I got to thinking.  What if one person or a group of persons was powerful enough, or had enough political savvy to unite the world under one flag, or government or dictatorship, or republic etc.? My question is would it be the right thing to do?  I'm in two minds and per usual because I like to argue both sides of points in my head. 

Side one, it would be wonderful not to have the stress of countries trying to expand their boarders, to be able to institute rights (for example, women in the middle east and the gay population in Alabama).  There would be no stress of another world war III, and everyone could cooperate to rooting out terrorists.  And terrorist would have less people to find asylum with if they were not trying to over through another government.  It would still be around but then again maybe it could be better.  I think of it as vaccinations, they hurt a little and can maybe cause autism but they make the world better.

Side two says this is terrible.  Forcing people to be under one system is an atrocity.  People should always have a right to choose who they want to follow, even if following means war, and death.  It is their right to make those decisions for themselves.  If they want to subjugate women, or blacks or whites or hispanics or males then it is their right to try, but it is also the right of the afore mentioned to rise against said subjugation.  In other words regardless of the greater good, peoples choices always come first.

Another question I have is why is that everyone who seeks power (I'm speaking politically I guess) are never good at carrying the mantel when they have it?  But those who it is thrust upon wear the mantel so well (G. Washington for instance).  Perhaps it is the want of power that taints the person doing the seeking?

-Zachary