So far, the flashback has been shaping up very nicely. The Scabbards are being well characterized, which is important, as I feel sympathizing with them is more important than with Oden since they are our living players in the arc, and where the emotional stakes are at their highest.
My one worry moving forward is if the arc becomes muddled with too many characters. We'd lose sight of where the focus is. Even now, Kaido's presence as an antagonistic force is so diluted with Orochi taking the spotlight on villainy, and Linlin arriving as a comparable force of power.
To see something like this extend to the heroes, where the Scabbards, or even the Strawhats get lost in the shuffle during the big war will lead to an unfulfilling experience.
Still have faith in Oda to weave all these threads in a cohesive fashion.