I must say that stamina musn't be out since most of the games out there have stamina for a reason. First stamina makes you to play longer in terms of days and slows down progression. Second without stamina you will start the game almost at high lvl right away. That reminds me of a game that i played on facebook called marvel avengers alliance. The thing that kept us from finishing all the maps and do non stop grinding for equipmwnt and stuff was the stamina. And that was actually great if you imagine everyone having everything in an instant without spending money, of course there were some stuff thqt only money could give but it was ok since even those things could be easily countered. Now i went a little of f topic so i stop here.