My hopes were threw the roof when Kotaku said that the D3 team came & talked to Bungie about loot.
The trouble is that Destiny is a fundamentally different end game with different activities, each with their own loot tables, and different itemization priorities and levels.
For example, there's no max item level or attack value in Diablo. Items roll with ranges on perks.
Destiny ties everything to gear score, drops items of varying ilvl, has a tier of items above legendary, has weekly loot lockouts and every perk is binary. Additionally, all of Destiny is balanced around PvP, a huge complication.
Destiny's light system, the gear score, gives a sense of an end state, especially in Year 2 when it's impossible to get there. How many people will quit when they hit 320 or quit because they feel like "the goal" is 320 and never get there. The true end game should be finding gear you love and building a set to make it awesome. Think about your raid gear. Touch of Malice, Hung Jury, Spindle, 1kYS, for everyone here. How boring.
That idea of an fixed end state doesn't exist in Diablo. The D3 end game centers on building sets, then improving each set item. Diablo loot doesn't have to be balanced and their whole ethos is making the player feel awesome and abilities feel powerful. Some builds and sets will always be strongest, but you can progress without always doing the hardest thing there is. I can progress doing Normal rifts or Bounties just as much as pushing the highest Greater rift I can. Normal rifts give me Death's Breath for rerolling or cubing. Adventure mode gives me keys for ubers, DBs & cube mats. Greater rifts give me tons of blood shards for Kadala.
This is crucial, I can feel like I'm progressing no matter what I do. As opposed to Destiny which puts that light number on every screen and makes that the biggest number on every piece of gear. And then to make decisions that make something fun, that number will go down? How does that make sense?