My ideal scenario?
A fleshed out Mihawk vs Sengoku to give him elite feats and a victim, to give Mihawk his full flowers have him body Sengoku mid-high diff at worst. Then Shiryu somehow kills Mihawk, doesn't have to be fully onscreen to hide Shiryu's new awakened abilities or df, then Zoro vs Shiryu becomes so much heavier
Even though I fuck with Mihawk, this adds so much more intensity to the story over a student fighting his mentor in the middle of the world ending lol. And it would also cement BBP as final villains.
Thing is it's a pipe dream given Shiryu's Hachinosu portrayal, he isn't being portrayed like he is gonna be taking down someone like Mihawk.