I think everyones rankings of the captains went out the window with the final arc, so many new abilities, poiwer ups, Kenpachi bankai, Unohana revealed to be more powerful than a lot of people were willing to think prior to that revelation, seeing some bankai that maybe were a bit underwhelming
ery true man. the one I am most impress with is Byakuya. why because his shikai turn into his bankai and his bankai got a huge power up. however though, the strongest captian right now is Shunsui without a doubt