This game needs more interactions with other players. Especially with friends all you ever do is challenge them. It is nice that you can see who you fought with after battles but that is literally all you have.
Here are some ideas I come up with that would increase social interaction within the player base
Create a mode where players will have to cooperate to either defeat a really strong enemy or waves of enemies. This mode can be activated either travelling there or simply be a separate battle mode.
DNA market exchange: Bartering and exchanging DNAS with other players. Of course the dev will have to enforce a fixed rate of DNA to prevent players from boosting others. So like 1 epic DNA is equal to 100 rare DNA for example. The market can be reached by travelling.
Chat option. It is boring walking alone getting DNA from far off neighborhood. Chat option allows you to talk with friends and let them know of any epics you might see. This can create a stronger community base.