I am enjoying this game, do not get me wrong but the keys are too slow. You get 1 every 3 hours which means you can open 4 fine chests in 12 hours and if you get the better chests you are waiting 6 to 9 hours just for one chest to be opened.
Because at higher levels it takes longer and longer to advance, which you can only get experience from unlocking chests from battles you have won, you only have 3 slots, you cannot drop any chests. Sometimes I have 3 simple chests I am waiting to unlock and there is no garuntee that you will win the next battle.
I am thinking maybe if you keep battling you can, say maybe winning 6 battles will get you a key. If you let us get a key every six battles we win along with the other ways it would allow us to make some progress.