I tried to avoid filling things that I thought interesting because we do need some significant inland bodies of water. Earth has the Great Lakes, lake Victoria, the Black Sea, the Caspian Sea. Just look at the Canadian shield its riddled with very large lakes.

Perhaps we can modify your original suggestion and put stuff in the blue blob and put those super long islands next to it?
Click image for larger version. 

Name:	New Co-op proposal suggest1.jpg 
Views:	81 
Size:	745.4 KB 
ID:	66358