- Changes to get the map more inline with the terrain ruleset: all jungle tiles now have a plains base (lots of them were on grassland), ice does not have forests on them, also no forest on marble, and probably some more.
- Added much more marshes. Added a few atolls (including Midway) in v 3. Corrected a bunch of rivers.
- Changes to account for bigger city radius: some resources that were out of reach for the capital in Rhye's Civ4 original could now be obtained by the capital so I changed those. In general all resources close to starting locations (including city states) were reviewed.
- German and Siam start closer to their historical locations, Egypt one tile down so they can found the (roughly) Alexandria location, added horses closer to Greece, ...
- Less luxuries in Europe, but more resources on the map in general. In v 3, I added some oil to a.o. Europe and north of Japan (locations backed by research). It would be strange to have a WWII without tanks or fighter planes.
And a bunch of cosmetic changes I can't remember and really no one would care about