Because information doesn't translate into having the mechanical ability to do something.Sorry - but i really have 0 idea what you are talking about. Why do you need to learn on a regular basis if you have all informations?
Points one, three and four are all applicable to Diablo 2. Define "more aggressive".-Special Mobs gain new affixes per difficulty
-Number of affixes grows (n 1, nm 2, hell 3 and inferno 4)
-All mobs get more aggressive
-Size of packs grows
-more hp and damage (but that's to be expected of course)
So i would say this qualifies as "fundamentally more challenging on higher difficulties"