For Easy: So, shouldn't that also mean well, less rewards?
Already happens, a I mob gives less chance for silver or gold than a III mob.

Because otherwise, besides challenge and we all know that's not a incentive, why even do the harder content if I could Duty Finder 12 people, go in and mow down easy mobs for easy loot?
Not lots of people going on Diadem easy for the 'better loot'. I'm personally going to get eso, and the achievement (do 100x easy, 100x normal 100x hard), or I would only do normal.