I think one stamina for every 10 minutes is not enough to recover from grinding for mats for gear and also trying to get your time in the Labyrinth for your Daily's. It forces you to choose between trying to level up hero gear or trying to get tokens for spirit plans to get your 6-set. I think the time to recover should be more like one every five or six minutes instead of ten. Yes there are other things to do that don't require stamina while you wait but you can only hang out in the arena for so long before it gets really boring. Once you've used up all your coins in the temple and credits in the tavern there's not much else to do while you wait.... except hang out in the forums I guess. Having to wait all day in order to play the game is not going to get you a lot of long term players. Players need to have a way to get more stamina if they don't have the gems to buy it.

And speaking of gems... 20 gems to recover 25 stamina is completely ridiculous. That works out to about 1 gem per monster for roughly 1K experience. WAY overpriced imo.