I don't know if I agree on that one. Even in the earliest of EU works in particular Truce at Bakura, that's more or less exactly what the Rebellion sought to achieve after Endor. I understand that it would inevitably descend into decadence with opportunists like that Borsk F'eyla character, but what exactly were the planets supposed to do for governance afterward? Wouldn't the fabric for storytelling be a bit more difficult to tell with only sovereign planets? I don't know but the concept for the New Republic seems to go back a long way.