The following is a video from an old D.I.C.E. event of former Blizzard North executive, Bill Roper giving a speech about the aspects of rewarding players.
It’s an interesting lecture which sort of explains why a lot of us found D2/LoD fun (the quest for loot).
Challenge/difficulty (which I have no problem with) has to be balanced along with the loot. Until I got to Inferno, I didn’t really get some of constant criticism that was taking place. Once I hit the gear wall in 2nd half of Act II, I now see why some weren’t having fun (imbalanced affixes, drops that don’t necessarily help you feel like you can progress unless you head over to the AH, etc).
My original post on the official forums: http://us.battle.net/d3/en/forum/topic/6019813422#17
Game design and its reward structure are not a fluke…