Gintoki is stronger than Takasugi because he's Shiroyasha and I'm not saying that Takasugi is weak, just not as strong as Gintoki (he didn't want to kill Takasugi that's why he didn't fight him full-power like when he fought Hosen, for example) and the Yatos, who can kill him easily (especially Kamui, who wants to fight him). Okita 'can't' kill Hijikata because of the comedy, but he's the one considered to be the best swordsman in Shinsengumi, so yea. lol