As we know, haki expert, history PhD, scientist, warlord and lizard master Kaido spilled the beans long ago:
As long as your Haki is superior the grade of your sword doesn't matter at all.
Why? One example. Oden would've broken kaido's club when they fought. Oden had 2 high ranked swords and high haki stats. But they weren't higher than kaido's. So kaido could've used a spoon against Oden and it wouldn't have broken neither.
You can guess it.
Mihawk will break fujitora's supreme grade sword with his supreme grade sword showing off as WSS.
Zoro will break either Shiryu's supreme grade sword (if he has one) and/or Mihawk's Yoru using his inferior blades.
Maybe later when fame and wealth comes, he might come across a supreme grade sword and upgrade. But I doubt Roger explicitly needed his sword Ace to reach the top. Neither will zoro.
As long as your Haki is superior the grade of your sword doesn't matter at all.
Why? One example. Oden would've broken kaido's club when they fought. Oden had 2 high ranked swords and high haki stats. But they weren't higher than kaido's. So kaido could've used a spoon against Oden and it wouldn't have broken neither.
You can guess it.
Mihawk will break fujitora's supreme grade sword with his supreme grade sword showing off as WSS.
Zoro will break either Shiryu's supreme grade sword (if he has one) and/or Mihawk's Yoru using his inferior blades.
Maybe later when fame and wealth comes, he might come across a supreme grade sword and upgrade. But I doubt Roger explicitly needed his sword Ace to reach the top. Neither will zoro.