Captain Commander should be on this list, as well. Blew his whole load (Bankai) on a doppelganger that only copied Juha Bach's likeness, and not his reiatsu. And this is coming off Yamamoto figuring out the secret to Complete Hypnosis by actually laying his hand on Aizen's sword. Dude has millennia of battle experience, but gets fooled by a damn copycat that couldn't even mimic the power level of a man who he fought with in the past. Then he gets completely overpowered and peaced out in a way ill-fitting of someone of his stature. I'm GLAD WSJ put the screws to this hack. Next Thursday can't come soon enough. Good riddance.
To be fair, Yamamoto being a dumbass is one of the only things Kubo was consistent with.