Death Timers.
So we get a 5v5 teamfight in the midlane and by the time the teamfight is over with us getting an ace the deathtimers of 3/5 of the members of the enemy team are 10 seconds or less from being back up.Riot can you do something about this? Why is baron so essential to ending a game? Why does 1 epic monster have a bigger impact on my game than getting an ace? Death timers need to be longer in the late game and baron shouldnt be a necesity to ending the game.