Here's a few things I would do:
1. The game has different tile sets for different continents, make more use of them, use the American autumnal forest to represent a different kind of forest or taiga (actually i suppose that would be pretty inaccurate considering taiga is pines mostly but whatever), use African / Asian mountains for non snow capped peaks like the Appalachians or the majority of Australia's mountains, use European snow capped mountains with grey rock for arctic and European mountains, but use American snow capped mountains with brown rock other areas like the Andes. African hills in desert appear as sand dunes, The Sahara, Arabia and parts of Australia's desert have large dunes.
2. Add custom resources accurate to world placement, ie: Oil in North America, the gulf of mexico and to a lesser extent south america. Also Russia and the middle east have a ton of oil, other areas have smaller amounts or none at all. Add pearls in pearl production regions, uranium in uranium production regions (there is uranium in parts of russia, australia, north america, scandinavia, other areas have less deposits. Gems in gem prod
3. Australia has no inland lakes like the ones pictured. Ignore world maps. We simply do not have viable lake resources in the desert. They don't exist. What does exist are empty salt lakes that fill up every decade or so with seasonal rain, in which case they are too salty to irrigate with anyway. Everyone seems to get this wrong.
4. Greenland has small habitable areas on the south west coast and north east coast, pretty much tundra (as opposed to icecap/snow).
5. Do anything you can to help land starved European civs.
6. Make the Himalayas Tibetan Plateauless big in China and more big towards India as China need to expand more than India does by far. Indias ability means they will tend to build less cities and hence need less space.
7. Make Japan bigger, they're pretty starved for space in their starting location.
8. Less mountains in southern spain. Less rivers in Europe maybe just the Rhine and Danube in the France/Germany area. More space in Italy/Greece
9. The Atlas mountains in north western africa need to be a bit more pronounced, the coast between egypt and morrocco/carthage/whatever should probably be more desert and less plains.
Just my 2 cents.
Like the map so far very much.
