Two things that came to my mind:
- Maybe some of the lines are too thick or too black. Maybe try making the coastlines dark blue and the outlines of the mountains a bit thinner? Just an idea.
- Some of the labels are nearly unreadable, especially the ones above the mountains and the bright ones on the land.
Apart from that: I love your idea of a patchwork world and the consequences of sticking unrelated regions together! Really, really cool.