Mihawk will never be more relevant than the characters involved with one piece actual purpose.
Mihawk existence as swordsman revolves around zoro's dream which speaks more about how important zoro is that a whole top tier exist just for zoro and not Mihawk per se.
Obviously he's important as he's tied to Zoro but will he be more relevant than likes of Teach, ImU, shanks, Navy to the story? He never was and he never will be.
Also, I feel we might not see the arcs like expected.
When oda said it's battle royale then he just not meant yonkous.
It's everyone's game - Navy, RA, Yonkous and WG to get one piece