Kintarou probably didn't develop Yips because Ryoma was trying his hardest to win the point. They both used every move they had. Yukimura, on the other hand, simply returns every shot, no matter what kind of shot it is. That makes an opponent lose confidence. That's where the yips comes from...
1) Yamamoto
2) Aizen
3) Shunsui
4) Kenpachi
5) Byakuya
Not counting Urahara, yoruichi, or Isshin. Hard to estimate their powers. Ukitake is always sick, so that knocks him down.
Even though Krauser has power, Momo's BJK will whip him. The BJK would probably break Yagyuu's wrists if he tried to return it, but he's smart enough not to try unless he has a trick up his sleeve. Taira isn't anything special, but he'd get the job done.
Yagyuu's laser would pretty troublesome...