Because of medium and hard difficulty didn't provide any incentive or bonus to the players, the player who wants to grind at Inferno effectively can only either choose Easy or Master 1. There is no in between for the player to choose.
As least for PC version, the player can steadily increases the Monster Power when he felt that his character is too strong for current monster level (mp 0), and can go slightly further for better chances of getting items at next MP level (mp1).
In console version, as long as your character cannot survive in Master 1, you are forced to farm at Easy until you get better gear for Master 1 even if your character can One-shot everything in Easy Mode.
Something must be done for the difficulty mode.