I was thinking of something like the Vietnam War, but since you could add more players why not a map of the Cold War? It hasn't been done yet, and with strategy it could work out really well.
The Spanish Civil War and the American Revolutionary War would be interesting as well.
Here's our official WL Mapmaking Discord as well:
https://discord.gg/DHERfnT
Edited 2/16/2018 02:12:29