You know, it would be a really fucked up twist if after this whole arc about changing the present state of things by overthrowing the current relationship of power and building a new world, things actually didn’t change for the best.
Let’s assume that the Washuus and Aogiri will fall by the end of next arc: there will be a vancancy of power in the two most important factions of this war. neither ghouls nor humans will have a guidance, and things will go back to how they were before the institution of both organizations: homo homini lupus.
Not to throw any philosophical speculation into all of this, but I don’t think that killing off the leaders will change the beliefs of ALL the followers. History as well as fiction has always shown us that tyrannies get replaced by other tyrannies, as long as the fundamental truth that people want to be led remains unchanged.
So what if, during that vacancy and chaos, a neutral party will take over? (I’d say the Clowns for example, but I don’t reckon they’re interested in being the main actor on stage; they’re hedonists, so they probably just want to watch). I don’t think that things will change as fast as people die. A “good” hero can only exist as long as there’s a Necessary Evil to fight.
Of course there’s also the fact that Kaneki is not a Inherently good character. No one in this manga is, actually.
I don’t think that he will only do positive things in this arc, tbh. He’s still facing a loss that impacted him really really hard. Sure, his mindset changed a bit and for the better, with him finally realizing that he’s worth living. But at the same time we shouldn’t forget that he was basically set up for this role by two of the most abusive parental figures he’s ever had. They manipulated him into becoming the king out of necessity, fighting a greater Evil. Sure, the final choice was up to him, but as I said he was in a fragile state of mind. Of course he would say yes. And I’m worried that as much as he’d want to change the world for the better, he might still be unprepared for this role. That’s why I always thought that Amon and Hide were necessary allies for when he had to take the role of the King. They’re his pillars, his Humanity and his Morality, and they keep him grounded. But as of now, he doesn’t have either one at his side, and this isn’t even his revolution. This is Arima’s and Eto’s.
So what will he do, once the bad guys are defeated? I don’t think that his role in all of this is that of being a morally upstanding Hero. He is gray, his parental figures are gray, and this whole plan of bringing down institutions of power by violence is gray.
So, in the end, what exactly will change? Who will hold power once Kaneki is done? How would that be a better world than the present one?