Will Oda devise new advancements of Haki?

[SSJ2]

Do you think we've seen everything now as far as advanced Haki goes, or will Oda pull some surprises out of the bag?

 

[Future Warrior]

I think so. I can't imagine Shanks being held in reserve for so long only for him to use ACOC coating.

Secondly, the story has consistently put Shanks in a more favorable light than Mihawk, which requires some justification considering the latters WSS title.

 

[SSJ2]

And what's the consensus on Mihawk? He must have Haoshoku if he had the will to become the world's strongest swordsman. Otherwise how the hell is he keeping up? Maybe he has a further advanced type of Busoshoku.

 

[sei'taer]

Shanks has the ability to cancel advanced observation, so that has to be some sort of Haki use.