first don't include yahiko with nagato,yahiko's way was the same as jiraya's,he wanted to bring a peace treaty and stop the war in a peaceful way,nagato is the one who changed that after his death.
now some say people may fear pain,but we've seen that humans once hurt they'll try to get back at the one who hurt them,even if it costs them their lives,so the ones in control of the wepon of massive destruction will be wanted by the payback,and the world will enter in a never ending cycle of revenge.nagato was dumb to think such a way will work.
love and understanding,and using peaeful means to end conflicts is great and only effective if it's backed up with enough power and respect to listen to that person.not to mention there's some individuals that it's useless to try to convince ,we've seen when yahiko wasn't strong enough he got killed and nobody listened to him from the big nations.
sasuke's way is not effective,even if you eliminate the sources of power humans will still fight,if you try to force them they'll fight back.
obito's way is plain slavery and completely irrational,i mean how can obito know what's inside every person's brain and let them see their perfect world?having the juubi might give him chakra,new abilities,but not enough braincells to control every person's illusion into their desires,unless the genjutsu will automatically make them see their dream world throuht another PNJ induced uchiha power-up.nd if he casts an illusion that everybody will live in it together it will be his own perfect world only,every person has his own vision of the perfect world,his dream world might be a nightmare to others.
not to mention this guy controlled one person(yagura)and look what happened in the mist: bloodline purges,civil war...
