I don't know
I don't think Oda really cares about that right now
I'm not expecting it to happen
But i hope it does
Oda's convinced everyone that Zoro's backstory and plotlines will be left unresolved, so the reveal hits hard.
Oda introduces a character, their motivation/characteristic, and resolves their story through both.
Nami steals. Nami steals from people she cares about to save people she cares about, and then gets stolen from.
Vivi sacrifices. Vivi sacrifices her youth/innocence to join Baroque Works, sacrifices her friends to flee, and is almost sacrificed, before sacrificing a journey with her friends to stay and fix Alabasta.
Potential Spoilers ahead, I'm confident about this theory
So, what is Zoro's defining trait? He's lost. Here's the questions I've had about Zoro.
-Why is Zoro lost?
-Who are Zoro's parents?
-Where did Zoro come from?
-Why has Enma not been used to kill Kaido, when killing Kaido is what the sword desires? Why bring up that plot point?
-Why is Zoro constantly called a Demon, and referenced alongside Hell and the Underworld?
-What happened in Zoro's mind with the reaper while Franky was carrying him?
-Why did Ryuma give Shusui to Zoro?
-Why do Ryuma and Zoro look alike and have similar scars on their eyes?
-Why do people from Wano constantly compare Zoro to ancient Samurai?
-Why so much focus on Ancient Wano?
-Why is Oda so secretive about Zoro's father if it's not important?
-Why constantly connect Zoro to the Shimotsuki?
-Why were Ryuma and Zoro compared to each other during their fight in Thriller Bark?
One final question.
Who lived in the past and was connected to Ancient Wano, and is known to send Samurai to the future?
The only conclusion I've found to satisfy Zoro's plot points is that he's the son of Ryuma, sent to the future by Toki. He's a Samurai LOST in time. Kinda like
Gotta Get Back, Back to the Past, Samurai Jack