Kizaru's not BM or Kaido. He's not as easy to fight as they areβhe's among the most refined fighters in OP verse. Zoro is far from perfect; remember that Rayleigh and Mihawk are basically Zoro with much better haki stats, better raw fighting skills, and have a much better experience. That's what it takes to match Kizaru. Zoro's not ready to dance with him yet.