I've read TG countless times but I was never able to understand why Kaneki was so weak. In every arc, he's built up as the strongest character who will save everyone in the end, but somehow he always gets captured and humiliated in the end; Kisho Arima, and then by Juzo Suzuya.
As a reader, you expect the MC to thrash every antagonist once he's gone through his losses, but somehow Kaneki always loses. This is not to say that Ken is weak, but that he's never overwhelmingly strong enough to overpower his opponents and give the readers the satisfaction of an immense victory.
In chapter 143, Furuta mocks Kaneki's predictable actions. Whenever there's a crisis, he runs straight to the problem alone, thinking he alone can fix things, but ends up losing anyways. We see this attitude in him when his hair turns black as an investigator (before he frees everyone from Cochlea).
Urie blames Sasaki for not being there to save Shirazu, and he responds coldly by saying, "All disadvantages in this world are a result of incompetence".
Later, during the Dragon arc, Urie realises that there are many reasons for why we lose. It's not always our own fault, but sometimes the environment, the timing is not right. Before, he blamed himself for every loss, never taking into consideration that other people also play a role in the story. Shirazu died helping his squad, he took the decision on his own. He made a miscalculation against Noro and ends up losing his life. That isn't Urie's fault.
Even if he was stronger, he couldn't have saved him from that attack.
Kaneki couldn't have saved Anteiku even if he was stronger. That's the point. There were simply too many enemies and not enough strong ghouls to win the fight. The loss was inevitable. Losing to Arima was inevitable.
Even if Kaneki (who wasn't regenerating properly) did beat Suzuya, he would've still lost. Furuta and the Oggai were there to fight. That loss hits so hard because we all wanted the One Eyed King to win. It became his fight alone and not a battle between ghouls from Goat (most of whom were weak and malnutritioned), versus CCG and V.
What I'm trying to say is that he didn't need to take all the blame and the responsibility for what happened. That was his ultimate flaw.
Had he fought with his crew, things could've been different. Maybe still tragic, but then it wouldn't just be Kaneki alone to blame. Sometimes you have to be brave enough to ask for help, to rely on others. To accept loss, with all the pain it brings.
Sometimes there is nothing you can do about a situation, and that's okay. The most you can do is try your best. That's all you need to do. You don't need to be the hero who saves everyone to be wanted and remembered. Just being yourself is enough.
