Sandai isn't Yubashiri.
Wado Ichimonji is tied to Zoro's promise to Kuina. His most important sword.
Sandai and Enma are important milestones.
Sandai was Zoro's first "personal claimed" sword. It was AFTER his duel against Mihawk. A turning point on his path to WSS. The blade acknowledged him and his resolve. Yubashiri was just a bonus he got because the sword shop owner liked him and Oda needed to give Zoro a 3rd sword. couldn't be some generic one.
Shusui was also claimed by zoro by defeating Ryuma's zombie. Ryuma is his ancestor and, as far as we know, the strongest swordsman to ever live in the story (sry Winhawk bros). It was also Zoro's first Black Blade, although he wasn't the one to forge it. He still have to "tame it". Replaced the bonus gift Yubashiri as another sword Zoro "claimed" on his path to WSS.
Garbage, I mean Enma, is Shusui's replacement. Although zoro didnt "claim it", he still had to improve himself in order for the blade to accept him as its master. Think Sandai 2.0 on steroids. Yet another important milestone on Zoro's path to becoming WSS. Helped him unlock CoC.
So you see, all of Zoro swords have important narratives for his WSS storyline, except Yubashiri, who was just a filler sword so Zoro wouldn't spend the entirety of the Paradise with 2 swords.
Stop thinking it means Sandai will break just because you junkies want him to get a "greater grade" sword. As Mihawk said, ANY BLADE can become a black blade.
Stop powerscaling his fucking weapons.
