I hate how the old world maps are hyper-accurate and modern while the new world is crude and fanciful.
For example, the map of Dnieper Basin anachronistically depicts lakes and reservoirs that only existed in the 20th century. Prior to 1927 it looked more like this:
Similarly, Yellow River shows the river in its modern course north of the Shandong peninsula when it actually ran south of it for the vast majority of the time period.
They should have a consistent style for all maps that isn’t just a lazily copied modern map. In my opinion, basing it on something from the late 1700s or early 1800s would look the best. It would still have a bit of a crude look, but by that point, almost all of the world was explored (but not all so there is still room for “Unknown” maps) and the maps were fairly accurate.