Very nice concept indeed, however, the scoring system needs to be more advanced (harder to farm coins) for power users and hardcore gamers/runners.
GPS cheating is a big issue, and I hope that you have some new ideas, hopefully, better than Nintendo, to prevent simulators (or other ways of cheating in location) to fake the location. This is crucial for the fairness of the game and has significant impact on its reputation.
Also if you are targeting as many users as you can, graphics of the game needs to be more attractive. Now it is quite formal and neat but for example for teenagers or even adults, it may become boring after a while since other mobile games put a lot of efforts graphic wise in their game to make it as attractive as it can be.