We are just stating our personal opinions ^^ Hm, I understand the argumentation. But that is the reason why a lot of people are frustrated. And at least for the first game the highest difficulty mode was mainly for the challenge. For people who wanted to play the game for playing the game. I mean if you stop as soon as you have everything it is a bit sad. Although we all want to have this feeling of completion at one point (I orientate more on the achievement side).
Well, you could categorize the Deeds as well. So that you are getting the difficult Deeds with the more wished for chests only at higher difficulties anyway.