TBH, both of them suffered due to Oda's excessive indulgence of the shine of waste side characters. It has been so long since Luffy has driven the plot/had a character moment (nothing since chapter 949) and Zoro had any good character moment. Both characters did nothing more than just fighting big baddy and 2nd big baddy throughout the raid. I am against ZKK but Zoro's backstory/visiting Ryuma's grave/Nidai Kitetsu plot/double the backlash of the mink drug plot could have helped him as a character before leaving Wano.
Baby Mihawk thing is interesting though. They have made similar thing to Hancock. Literal replacement of warlords. It is as if they are trying to replicate the powers of all strong characters via pacifists. This can lead to an interesting development and bring massive hype in the final war. Imagine building a massive army based on the powers of all the strong characters in the verse including Roger,Rayleigh, WB, Xebec, etc. This SSG plot has so much potential. This is better than reviving dead characters like Naruto's final war.