@G_soildier:
What was the balance of the world like before the warlord system? What. Broke( or brought about this ) the balance(imbalance)
I don't think the balance would have been a concept or Gorosei obsession prior to the great age of Pirates. It comes off like something that has come together in response to that. Similarly I think that there was no concept of the Yonkou before Roger's execution either, so yeah probably no Shichibukai either. Admirals of course, but that should go without saying.
I imagine that with the Great Age of Pirates starting, pretty quickly the amount of super strong pirates dramatically increased, and so the amount of pirates near the end of the Grand Line also increased of course.
The Yonkou concept would have organically formed from this, with the four strongest (Whitebeard already being an established superpower) being recognized as particularly dominant. And forming a sort of Cold War situation that more or less paralyzed pirate movement in the New World as four or so mega pirates and their empires entered into a Mexican stand off. And THAT is the balance of power that matters most of all to the Gorosei. It has to be. The balance between Yonkou.
The Warlords and Marines play their roles, the government's perfect ideal would obviously be to control the New World and at least not really have a pirate menace existing in it much at all. But that's ideal, not the reality.
The balance is more about that, and lo and behold destabilizing the Yonkou is what Law's plan involves.
The Gorosei's number one interest is balance, because they are fine with a Cold War freeze in the New World, because it keeps anyone from advancing on Raftel.