Luffy cannot defeat Saturn because he still needs to beat Kizaru, who will always defend Saturn.
That begs the question of who will fight Saturn? Imo, likely Kuma.
Vegapunk’s brain circuit allows one to have split personalities. And he was doing experiments on Kuma’s memories. Chances are that each of the pacifista have a split personality with Kuma’s memory.
Given how much of a saint kuma was, his personality is the ideal for the pacifista.
imo Vegapunk will trigger the brain circuit and cause the pacifista to rebel against the marines, turning the tide of the battle.
With Kuma’s personality, the seraphim will take on Saturn to save Bonney. Ultimately leading to a repeat of this:
Overall it just makes no sense for Saturn to be outright defeated this arc. Much like Jack in Zou or BM in WCI, Saturn will lose and it will be a monumental event(as Luffy’s crusade in WCI was). Yet it is simply too early for a gorosei to fall.
Hence I think the seraphim would be a good tool for Oda to use to stall Saturn.
That begs the question of who will fight Saturn? Imo, likely Kuma.

Vegapunk’s brain circuit allows one to have split personalities. And he was doing experiments on Kuma’s memories. Chances are that each of the pacifista have a split personality with Kuma’s memory.
Given how much of a saint kuma was, his personality is the ideal for the pacifista.
imo Vegapunk will trigger the brain circuit and cause the pacifista to rebel against the marines, turning the tide of the battle.
With Kuma’s personality, the seraphim will take on Saturn to save Bonney. Ultimately leading to a repeat of this:

Overall it just makes no sense for Saturn to be outright defeated this arc. Much like Jack in Zou or BM in WCI, Saturn will lose and it will be a monumental event(as Luffy’s crusade in WCI was). Yet it is simply too early for a gorosei to fall.
Hence I think the seraphim would be a good tool for Oda to use to stall Saturn.