@Bloel:
Dragon's presence is irrelevent, Kuina couldn't have joined the revolutionary army. When Zoro and Kuina fight for the last time there's a full moon (here) she dies the next day. The gap between Zoro seeing her for the last time and her 'death' (for the record i believe she did die) was one night. The night dragon spends at the dojo has a half moon (here) meaning it was not the night of her death, she could not have left the dojo on that ship to join the RA.
What? The link with the revolutionary army was after Sabo's supposed death. I'm not on either side, but I like the idea of the injured yet living person being
As for Zoro's screen time, flashback wise. It is important to remember that One Piece was only just starting, so extensive screen time, as was the case with Norland or Robin could have meant the death of One Piece in Shonen Jump. The argument that there is more to tell, particularly after it was revealed the revolutionaries stayed at Zoro's island/village after the incident at Sabo's town, still stands, but this must be taken into account.