I never believe that you cheat because of your great service and generous giveaways. It wouldnt make sense.And I dont believe on players cheating.
A ranking list would maybe bring transparency. I often was surprised on play store rankings, for example for flapper games how many points players can make. And a ranking list would give an additional tournament character. And its thrilling to climb up a few places on ranking. But I dont know if its very difficult to develop this table to an app.