Everything about that sounds nice, except that it is in some way related to Blizzard. Meh!
Also it sounds like implementing it would not be as simple as just making bosses drop at least one worthwhile item. I am hazy on how hard any option anyone is proposing would be to make happen, so I am not standing behind any solution for feasibility.
I would loot everything anyway, scavenger reflex, if it isnt nailed down steal the F*^&)#@ thing!
More unique item abilities is also a function of the rules, what can be bonused or buffed by an item? Remember in D&D ( back when it was new in the late 70's early 80's) when a +3 sword was considered awesome? There just wasnt any kind of powers on weapons, or very few, same for +1 Armor or +1 shield or anything else. Rolemaster the RPG really carried item based buffs and abilities into the range of coolness, heck I remember some items had 20 or so special abilities and could really be powerful or even godlike. I liked those items, and still would for D:OS. Hey I play single player only ever on any game, so I dont care about balance's I upset or being a megalomaniacal show-stealing greedy min-maxing munchkin-showboat. LOL aint hurting nobody but those mindless toons!
Some of the Legendary items we get in D:OS not only suck but are not useful at all, they are not prizes they are a waste of time, to loot, to evaluate, to even sell.