Big Mom's sword is originally a hat that she transforms. It wasnt forged by anyone how do you want it to be Supreme Grade?
Aramaki has a higher chance than Shiryu of having a SG by virtue of being stronger lol
Even if Aramaki is 500 times stronger than Shiryu, it has nothing to do with what We are discussing here
Aramaki's Weapon can be an Unranked Sword just like Law's
Not all Blades are Meito
So i'm not saying Aramaki's Weapon is Weak, it can be a Legendary Cursed Blade or whatever
But as long as it was never used, never acknowledged & not even Sheathed, i will not consider it a Meito in first place