Map system completation and spawn boss

Hi, I want tel my feeback about map this new map system , is very well and different , but i feel like i cant advance more because i dont have the good map.
The problem is : when you need spawn a boos you need actived a map with the good tier level and not because is good REGION!! ; so is more wasting time to get the good map tier and more difficult to get it , and that the problem ! i think ggg must make item currency can level up map in inventory based on true level on atlas or something like that , because we have the map but is not good tier -_-