The game has a open world map. Currently i don't think its good enough to explore the game because of no good rewards from the chests.

So i have some suggestions for the devs. 

Add secret letters of charachters released in a patch to chests (not secret letter clues).

This will provide incentive to explore the map for getting secret letters. As for existing chest.. U cam add secret letters.. And those who claimed chests will recieve equal amount of secret letters of the charachter via mail..

Maybe even add 'charachter shards' in legendary gold chests. 

As of now there is not much of incentive to explore tha game.