You can bet it wont be as bad as Naruto.
How are you so sure Oden was only talking about Wano?
Oden says, "If I fail to defeat him, there will be no others who can stop Kaido for a long time. Over 20 years ahead of us, there will likely be a massive war, terrible enough to split the seas themselves. In another 20 years, the primary figures of this great war will muscle their way into the New World. They are the ones who can strike down Kaido!"
^^ If I look at the entire monologue, it doesnt seem he was talking about only Wano.