How would you refute someone who trivialises Kaneki's development during the Aogiri arc (i.e. his transition from Kuroneki to Shironeki) as Kaneki goes from a 'wimp to a badass'?
Oh man, that classic argument.
First and foremost, Kaneki prior to his torture wasn’t a wimp. He might have viewed himself as weak, but then again Kaneki is probably his own worst critic.
Kaneki had only been a Ghoul for about two months when Aogiri took him. e started out as an absolutely ordinary college student, a normal kid that had never so much as tried to punch anyone. He was also a victim of abuse, having learned and internalized all kinds of unhealthy ideas about himself.
His hesitance to fight and give into violence makes even MORE SENSE now that we know his mother was physically abusive to him. Many victims of childhood abuse are fearful of becoming just like their abusers. This is another way in which the Black Goat’s Egg reflects Kaneki’s life – he lived in fear of becoming violent and abusive just like his mother. So he was even more hesitant to use violence, and feared both his power and how good giving into his instincts felt.
But even so, Kaneki was still pretty strong even before his torture. He learned to break arms through reading a book, broke Amon’s Quinque and beat him to a stand-still, and got in some decent hits against Tsukiyama. (Tsukiyama is compared to a World-class Boxer by another Ghoul, to explain his level of strength.)
During the escape attempt, Kaneki faces the S-Rated Bin Brothers alone. He manages to beat one of them in a one-on-one fight, through RIPPING A LAMP POST out of the ground and using it to beat the guy upside the head. Kaneki was strong even then, simply not on the same level as Yamori. That doesn’t make him a wimp, it just means that he hadn’t managed to hit the Big Times until the torture gave him a boost.
As we’ve learned in :Re, injury actually makes Ghouls stronger because it causes the RC pathways to spread through the body. So Kaneki’s torture gave him a huge boost, and then he further boosted it through eating Yamori’s flesh. In terms of his mental state, he reaches a point where he embraces the very things he feared before. While on the surface, it SEEMS like a positive change……the narrative proves to us that it ultimately wasn’t a good thing.
Kaneki went overboard, throwing away his support and trying to become as much of a monster as his enemies. He was an emotional wreck, sacrificing his sanity and his morals in a reckless pursuit of strength. And it ended up destroying him, while he was unable to save anyone that he cared about.
Neither state was necessarily a good thing. Kaneki simply traded one unhealthy attitude and coping mechanism for another. He went from living in fear of becoming a monster, to basically trying to force himself to be one as much as possible. And he ultimately realized it was entirely out of selfishness and fear, rather than to protect the people he loved.
Now, we’re seeing him repeating that pattern. He’s gone from being afraid, to kind of accepting things, to embracing cruelty and throwing away his humanity. These aren’t good things, and it certainly isn’t going from “wimp to badass”. It’s just going from one kind of damaged state to another.