There’s also the possibility of Shirahoshi’s capture. As we all know, Shirahoshi is an ancient weapon. She had powers that are enough to destroy the world.
We already know Caribou found out about this secret, and if somehow this gets out, then, she is sure to get captured, which will be huge, and essentially ring the bells for War.
But, there’s also the matter concerning Shichibukai. Fujitora has said that he wants the Shichibukai system to be abolished. Many other marines feel the same way. Look at Alabasta, for example. It was almost destroyed, but thanks to Luffy, they survived.
Unfortunately for Dressrosa, the damage was done long before the Strawhats even arrived there. Dressrosa was destroyed by Doflamingo when the Riku Family was overthrown. So, I think a lot of nations will support the idea of abolishing the Shichibukai system, which I think is going to happen.