I mean, no one would be aware of the entire world map at this time, yes. If you mean that the world should be different tectonically, no. Thats way far back a millions of years.
War Seas would probs take place where Greece would be, yeah. But there seems to be other European cultures around the place like the Vikings. Theres also references to Arthurian myth, (doesnt mean its literally Britain tho)
But yeah, mostly Greece.
For other Sea Clusters, I thought it was implied Old Sea was one cause the people of the Seven Seas actually came from the Old Sea. Trollus says theres “The Great Sea” mentioned in Online Fighting, but idk how this holds up, as Online Fighting is supposed to take place in the Old Sea? “The Great Sea” could just be its former name before people moved out.
Its possible the Sea Clusters could be based off of the continents, though last I checked, there’s 7 continents. Fun idea though.
Its not impossible that some cultures in the War Seas actually migrated from other Sea Clusters. I think its implied the people of Shell Island might be from the Seven Sea, they wear the same attire as Doom Island, and they lack last names like people normally do in the War Seas.
Ambanes also mentions other Sea Clusters and is looking for the Epicenter. I wont be surprised if dude also came from another Sea Cluster outside of the War Seas.
so the bronze sea and nimbus seas etc those seas are completely on the other side of the world and seperated from the other seas where the cursebeard war happened and stuff and only randal knows about it