So big brain theory time:
Shimotsuki Kozaburo, the swordsmith of Enma and Wado Ichimonji, had a son, Denjiro. 50 years ago, when Denjiro was a year old, Kozaburo left Wano country to form Shimotsuki village in East Blue. Denjiro is the man we know now as Koushiro, Zoro's master. This makes sense (the literally look the same) and it seems everyone is guessing it, not to mention Kuina inherited the Wado Ichimonji, which Koushiro must have inherited from Kozaburo.
Now here's the killer part: Zoro is Shimotsuki Ushimaru's son. From his sillhouette, the resemblance is uncanny. 20 years ago when Kaido took over and Zoro was a year old, Ushimaru tasked Denjiro, a scabbard who stayed behind, to save his son and take him to where Kozaburo set up his village to. Ushimaru dies fighting Kaido, and Denjiro, in order to escape with no trace, renames himself Koushiro with Zoro and his daughter Kuina (who is only a few years old as well). Perhaps his wife was killed by Kaido.
So Zoro, with the inherited wills of both Enma and Wado, is effectively the 9th scabbard "Denjiro", but nobody knows this yet.
I understand that people would rather Zoro be a nobody, but I think Oda is going this route anyway. He looks like Ushimaru's sillhouette and looks exactly like Ryuuma, who may be their ancestor.
I think Zoro may inherit Shusui and return Sandai Kitetsu to Kitetsu himself. He will have 3 blades from the Shimotsuki clan (Ryuuma is highly likely to be a Shimotsuki, his grave is in Ringo)