So here we go.
I do think the Revolutionaries will appear on Whole Cake Island, leading to the fall of the Germa Kingdom as well as to the fall of Big Mom. And here is why:
Firstly, we know from the recent chapters that Baltigo was destroyed and the current status and whereabouts of the Revolutionaries are unknown. So nobody can tell where they are and what they do.
Secondly Dragon has stated that he intends to make his move soon and even called for his commandants. So that means he might want to make way for the Reverie and attack the capital.
That leads to the conclusion that they could have destroyed their base on purpose to make it seem as if they were gone, thus they could technically strike at any minute and launch a surprise attack.
And then we have the Germa Kingdom. A mobile, ocean-going kingdom with many weapons and highly advanced technology which literally has EVERYTHING they need for this surprise attack. It could serve as a mobile base, they could freely cross the Red Line and also go to the capital whenever they want.
And then there are the Vinsmoke Brothers. We know that they do not have feelings. And who could fix that? That is right, Emporio Ivankov. He has powers over hormons and hormons are the reason people have feelings. He might be able to grant them emotions. And, despite of their douchiness, they are not at fault for what has happened to them. But they committed many evil deeds, but I do not doubt they can be redeemed. And helping the Revolutionaries who help people, especially commoners, could be a perfect way to redeem those characters.
The Vinsmokes also have the right to participate in the Reverie which could be the entrance ticket for the Revos to get in(for example by hiding in the Germa ships).
Then there is Judge, a king that stands for oppression and everything Dragon despises. So it might be possible that we get a battle between those two in this Arc.
And there is Big Mom who is also a queen and an oppressor(again: Revo issue). She has to go down as well. But Luffy is too weakend and exhausted to fight her in his current state. He is on the verge of death at the moment. His Vivre Card must be burning by now. And who would be pissed seeing that? Sabo, of course. I highly doubt he would not come to Luffy’s aid. He would not let his little brother die. I can see Luffy eating the bento Sanji has made and gaining enough strength to have a last battle on Whole Cake Island. But I can see Sabo fighting Big Mom with Luffy. We know that Prometheus and Zeus will be a problem and I do not think Brook is able to take them down(I see him returning the lifespans to their rightful owners later on, but not doing much damage to Big Mom). But Luffy will not be affected by Zeus and Sabo not by Prometheus. So they could work together in order to take her out. Brook could copy the Poneglyphs in the meantime.
Then there is another reason why things could turn out that way: The fact that there are only twenty chapters of the Whole Cake Island Arc left(only two volumes) and that there will be a Reverie Arc after that. And on the cover of the Reverie Arc storyboard there was a Dragon which indicates we will be seeing him there. But we need some sort of bridge between those arcs and the Revo’s appearance on Whole Cake Island could serve as that.
What do you guys think?
*Theory by PaperFlower